JP3399778B2 - Power system evaluation device, power system power flow optimization method and device, and power system planning support method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaluation technique for a power system configured to be interconnected, and in particular, the power system is evaluated based on the evaluation result to optimize the power flow, And apparatus for supporting the planning of the.

[0002]

2. Description of the Related Art When operating a power system, it is desirable to balance supply and demand so that the power system can be operated smoothly and economically. And for this,
It is necessary to evaluate the characteristics of the power system, such as economic efficiency, and control the power system based on the evaluation results.

By the way, as a conventional technique relating to the evaluation of such an interconnected power system, for example,
The Institute of Electrical Engineers of Japan, Volume B113, Volume 10, Issue 10, "Evaluation of Reliability of Power Generation / Transmission System Based on Demand End Reserve" can be mentioned.

Then, this paper discloses a technique for obtaining the output of each generator required to minimize the total amount of supply hindrance when the route of each transmission line is broken by a linear programming method. , There, the demand, the transmission line power flow constraint, and the generator output constraint are used as constraint conditions, and a formulation is performed in which the total amount of supply hindrance when the route of each transmission line is disconnected is an objective function.

In addition, when planning a transmission line extension plan for an electric power system, the evaluation of the effect brought by the transmission line extension is an important point. As a result of this addition effect, the reliability brought to the electric power system. And it is necessary to evaluate both aspects of economy.

In the above-mentioned paper, the amount of supply hindrance at the demand end caused by the upper and lower limit constraints of the generator and the transmission capacity constraint of the transmission line, or the margin until the supply hindrance (demand end reserve ratio) is used as an evaluation index. It also discloses the idea of supporting system planning by expressing the reliability distribution in the system by the level of supply hindrance and the level of demand margin.

[0007]

The above-mentioned prior art does not consider the variety of factors to be considered when evaluating the power system. For example, in the above-described conventional technique, the output of each generator is adjusted so as to minimize the amount of supply hindrance, but the total power generation cost in the power system in the normal operating state is not considered. As a result, if there are multiple power plants in the grid, there is a difference in the power generation cost of each power plant, so the output of each power generator may not be adjusted to simply minimize the amount of supply disruption. , There is a possibility that the total power generation cost in normal times will increase.

[0008] Further, the supply hindrance amount at the time of the route cut in the system does not become actual unless the route cut actually occurs, and the occurrence probability thereof is considerably low, so that there is such a condition. It may be economically advantageous to increase the amount of power supply disruption during a route break, rather than simply to minimize it, in some cases because it can reduce the total power generation cost during normal times. Furthermore, as the loss at the time of failure,
There is also an increase in the total power generation cost by forcibly shutting off some of the generators to stabilize the entire system in the event of a failure other than a route disconnection.

Therefore, to summarize the above, the output of each generator is quantitatively considered by taking into account the cost due to failure loss due to route disconnection, the cost due to failure loss other than route disconnection, and the total power generation cost during normal times. Optimization is a challenge. However, in this case, since the objective function is not linear, it is difficult to apply the linear programming as in the prior art.

Next, for the total power generation cost in the power system, the power generation cost with respect to the output value of each generator is obtained using the given power generation cost characteristic data of each generator, and this is summed for all the generators. Calculate by At this time, the reliability of the system can be considered as the amount of loss at the time of failure occurrence, but the above conventional technology evaluates this by the amount of supply hindrance when the transmission line route is interrupted.

However, as described above, as the loss at the time of failure, there is also an increase in the total power generation cost due to the forced shutoff of a part of the generators for stabilizing the entire system at the time of a failure other than the time when the route is cut. . Also, due to the extension of transmission lines, the power flow limit set in advance for each transmission line including the viewpoint of reliability
There is a possibility that the total power generation cost will be reduced by relaxing the (tidal flow constraint) and improving the output distribution of each generator. Therefore, it is necessary to evaluate this reduction in total power generation cost as an effect of the extension of transmission lines. In order to calculate this, it is necessary to recalculate the power flow constraint of each transmission line by adding transmission lines.

It is an object of the present invention to provide an electric power system evaluation device capable of obtaining a more accurate evaluation,
It is another object of the present invention to provide a power system power flow optimization method and device and a power system planning support method and device that use the results.

[0013]

[Means for Solving the Problems] First, the above-mentioned purpose is to quantify the cost due to failure loss at the time of route disconnection and at times other than route disconnection, which is a highly reliable and stochastic amount, and the total power generation cost in normal times. This is achieved by using an evaluation index obtained by taking into consideration the above, and by evaluating the power system by this, and further by controlling the output of the generator using this evaluation index.

Specifically, the above object is achieved by using the following means. First, the total load cutoff amount at the time of route disconnection failure and the load cutoff amount due to generator forced cutoff at the time of failure other than route disconnection is converted into cost, and The value obtained by summing the amount of change in the power generation cost is taken as the loss cost at the time of failure, and this loss cost at the time of failure is added up by the weighting coefficient given to each failure case, and this is added to the total power generation cost in normal times. This is achieved by using the evaluation index of the power system as the evaluation index of the power system.

Next, there are provided means for calculating a load shedding amount at the time of a route disconnection failure, means for calculating a load shedding amount due to forced compulsion of the generator at the time of a failure other than the route disconnection, and means for converting the load shedding amount into a cost. , Means for calculating the amount of change in the total power generation cost due to forced shutdown of the generator at the time of failure, and summing the load cut-off cost at the time of failure and the amount of change in total power generation cost, and summing this with a weighting factor for each failure case It is achieved by providing means for setting the loss cost at the time of failure and means for adding the loss cost at the time of failure and the total power generation cost during normal operation and outputting as the evaluation index.

In addition, the load compulsory cutoff amount at the time of a route disconnection failure and the total load cutoff amount due to the generator forced cutoff at the time of a failure other than the route disconnection are converted into costs, and the load compulsion amount cost is added to the generator forced compulsion amount cost. The value obtained by summing the changes in the total power generation cost due to interruption is taken as the loss cost at the time of failure, and this loss cost at the time of failure is added up by the weighting coefficient assigned to each failure case, and this is taken as the total power generation cost in normal times. This is achieved by summing them up as an evaluation index of the power system and controlling the output of the generator so that this evaluation index is minimized.

Further, means for calculating a load shedding amount at the time of a route disconnection failure, means for calculating a load shedding amount due to forced compulsion of a generator at the time of a failure other than the route interruption, and means for converting the load shedding amount into a cost. The means for calculating the amount of change in the total power generation cost due to forced shutdown of the generator at the time of failure, the load cutoff cost at the time of failure, and the total amount of power generation cost change are added together, and this is added by the weighting factor for each failure case. Calculates the loss cost at the time of failure, the means for adding the loss cost at the time of failure and the total power generation cost in normal times, and outputting it as an evaluation index, and the output of each generator required to minimize this evaluation index. And a means for doing so.

By the above means, the load cutoff amount and the total power generation cost increase amount at the time of the route disconnection and at the time other than the route disconnection are calculated and converted into the cost under the given system condition and various constraint conditions. The weighting factor for each failure case (for example, failure probability) is multiplied to obtain the evaluation index of the power system consisting of the total of the total power generation cost in normal times, and further, each evaluation index required to minimize this evaluation index. The output of the generator can be calculated.

Another object of the present invention is a means for calculating the loss at the time of failure and the total power generation cost in normal times, which are probabilistic quantities, by means of a unified and quantitative index, and each transmission line in the system after the transmission line is added. And a means for calculating the difference between the indexes before and after transmission line addition,
This is achieved by quantitatively and uniformly evaluating the effect of additional transmission lines on reliability and economic efficiency.

Specifically, the above object is achieved by using the following means. That is, first, in the power system planning support method that evaluates the improvement effect of reliability and economic efficiency by adding the transmission line of the power system, in the power system planning support method, the load forced cutoff amount at the time of the route disconnection failure and the generator forced at the time of the failure other than the route disconnection The load loss amount cost obtained by converting the total load cutoff amount due to the cutoff into a cost, and the sum of the change amount of the total power generation cost due to the forced generator cutoff as the failure loss cost. The cost is summed with the weighting coefficient given to each failure case, and this is summed with the total power generation cost in normal times as an evaluation index of the power system, and this evaluation index is obtained for the system before and after the transmission line addition, This difference is achieved by evaluating the improvement in reliability and economic efficiency due to the addition of transmission lines.

Next, in the electric power system planning support device for evaluating the improvement effect of reliability and economy by the addition of transmission lines of the electric power system, a means for calculating the load shedding amount at the time of the route disconnection failure, and a means for calculating the load disconnection amount at the time of failure other than the route disconnection. Means for calculating the amount of load shedding due to forced shutoff of the generator, means for converting the amount of load shedding into costs, means for calculating the amount of change in total power generation cost due to forced shutoff of the generator at the time of failure, and A means for summing the load shedding cost and the total power generation cost change amount and summing this with the weighting coefficient for each failure case to be the failure loss cost, and this failure loss cost and the normal total power generation cost, A means for outputting as an evaluation index, a means for calculating the power flow constraint value of each transmission line in the system after the transmission line is added, and a means for calculating the difference between the power system evaluation indices before and after the transmission line is added by using each of the above means. It is achieved by providing a.

With the above means, first, the power flow constraint of each transmission line is calculated for the system after the transmission line is added, and then the load cutoff amount at the time of the route disconnection and at the time other than the route disconnection and the total power generation cost increase amount. Can be calculated and converted into a cost, which can be multiplied by a weighting factor for each failure case (for example, failure probability) to obtain the total power generation cost in normal times.

Then, the value for the system before the transmission line expansion is subtracted from the value for the system after the transmission line expansion, and the result can be output as the reliability and economic improvement effect by the transmission line expansion.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. First, an embodiment of the present invention is embodied as a power system evaluation method and device for obtaining an RG index under a given state of the power system, and is further required to minimize this index. The present invention is embodied as a power system power flow optimization method and device for obtaining an output value of a generator. Here, the RG index is a sum of the normal total power generation cost and the expected loss loss at cost. Therefore, the smaller the RG index, the lower the operating cost of the power system. Since the cost is taken into consideration, it can be used as an evaluation index that accurately represents the suitability of operation of the power system.

The expected loss value at the time of failure is obtained by multiplying the failure loss for the failure cases listed in advance by multiplying the weighting coefficient (for example, the failure occurrence probability) assigned to each failure case in advance. In addition, the loss at the time of failure is the customer and the system that are generated when the protective device operates at the time of failure and the load cutoff is activated, and when the generator forced cutoff is activated at the time of failure other than the route interruption. It is the total loss incurred by the side.

The loss on the customer side at this time may be due to a power failure of the customer caused by load shedding, for example, and the loss on the system side may be, for example, forced shutoff of the generator (hereinafter It is conceivable that the total power generation cost increases as the output of each of the remaining generators changes in order to compensate for the amount of power generation that has been stopped due to electric control.

FIG. 1 is a functional block diagram according to an embodiment of the present invention. As shown in the figure, an input / output unit 1, a generator output adjusting unit 2, an RG index calculating unit 3, a power flow cost-constrained power generation cost minimizing power flow. Data generation section 4, load cut-off amount calculation section 5 during system disconnection, electronic control unit determination section 6, electric control amount calculation section 7, load cut-off amount calculation section 8 during electric control, load cutoff amount cost conversion section 9, and total power generation It is composed of a cost calculator 10.

Further, a system status database section 11, a failure database section 12, a parameter database section 13, and an RG index calculation power flow data section 14 are provided for holding various data. The input / output unit 1 is
Capture the input from the operator to the power system power flow optimization device,
Conversely, it functions to send each generator output value received from the generator output adjusting unit 2 to the operator or the generator output control device of the power system.

The generator output adjustment unit 2 is provided with various condition data (system configuration data, tidal current data, total demand data, generator output upper and lower limit data, fixed supply power output data, power generation cost) given from the system state database unit 11. Characteristic data, transmission line power flow constraint data, break point allowable power supply loss amount data, allowable power control amount data), calculate each generator output required to minimize the RG index, and output the result. At this time, the process is performed in cooperation with the power flow cost minimizing power generation cost with power flow constraint generation unit 4 and the RG index calculation unit 3, and the details of the process will be described later.

The RG index calculation unit 3 uses the condition data (system configuration data, system configuration data,
Total demand data, generator output upper and lower limit data, fixed supply capacity output data, power generation cost characteristic data, transmission line power flow constraint data, break point allowable power loss data, allowable power control data), and RG index calculation power flow data Under the conditions related to the failure case given from the unit 14 and the failure database unit 12, the RG index is calculated and the result is output. The details of the processing will be described later.

The power flow cost generating minimization of power generation cost with power flow constraint: The power flow data generating unit 4 is within a range satisfying each of the given generator output upper / lower limit constraint, fixed supply power output constraint, transmission line power flow constraint, and total demand constraint. It functions to generate tidal current data that minimizes the total power generation cost and output the data, and the details of the processing will be described later.

The load cutoff amount calculation unit 5 during system disconnection functions to calculate the load cutoff amount necessary for stabilization in the case of a failure that causes system disconnection, and output the result.
Details of the processing will be described later. The electric control device determination unit 6 has a function of selecting an electric control target generator necessary for stabilization and outputting a result for a failure case that does not cause system division, and details of the processing will be described later. .

The electric quantity control unit 7 has a function of calculating the total output value of the given electric power generators subject to electric control and outputting the result. The details of the processing will be described later. The electronically controlled load cutoff amount calculation unit 8 has a function of calculating a load cutoff amount required for stabilization with respect to a given electric control amount and outputting the result. It will be described later.

The load cutoff amount cost conversion unit 9 has a function of cost-converting the given load cutoff amount and outputting the result. The details of the processing will be described later. The total power generation cost calculation unit 10 calculates the total power generation cost from the given power generation cost characteristic data and output data of each generator, and outputs the result. The details of the processing will be described later.

The system status database unit 11 manages data concerning the status of the system targeted for power flow optimization and various constraints. The failure database unit 12 is
It serves to manage the data about the failure case for which the loss at failure should be calculated.

The parameter database unit 13 manages various parameter values required by the RG index calculation unit 3 and the generator output adjustment unit 2. On the other hand, the RG index calculation power flow data unit 14 manages the data necessary to give the power flow conditions of the system for which the RG index is to be calculated.

Next, the data managed by each database unit will be described with reference to FIG. First, in the system state database unit 11, as shown in the figure, system configuration data and power flow data, total demand data, generator output upper and lower limit data,
It provides fixed power output data, power generation cost characteristic data, transmission line power flow constraint data, break point allowable power drop amount data, and allowable power control amount data.

The details of these data are as follows. The system configuration data is each constant of system equipment such as impedance of a transmission line and rated capacity of a generator, and connection information between each system equipment. The power flow data is electrical data (active power, reactive power, voltage, etc.) on each system equipment such as a generator, a load, and a transmission line. The total demand data is the total active power of all loads.

The generator output upper and lower limit data are upper and lower limit values of active power output given to each generator. Fixed power output data is data that specifies active power output values for some generators. The power generation cost characteristic data is data that gives the power generation cost of each generator according to the output. The transmission line power flow constraint data is data that gives an upper limit of the active power flow rate of each transmission line.

The break point allowable power supply dropout amount data is data that gives the allowable upper limit of the amount of power generation for each of the divided grids that occurs when the grid is divided. The allowable electricity control amount data is data that gives the upper limit value of the amount of power generation insufficiency that is allowable in the entire system.

Next, in the failure database unit 12, as shown in the figure, failure point data, failure sequence data, and weighting coefficient data are given for each failure case. The details of these data are as follows.

The fault point data is data designating a faulty facility in the system. The failure sequence data is data that gives details of the failure and details of the system operation together with the time of occurrence. The weighting factor data is data that determines to what degree the influence of the failure case is to be weighted, for example, data that gives a failure occurrence probability.

Further, the parameter database unit 13 is adapted to provide initial value data of generator output adjustment width, threshold value data of generator output adjustment width, and load cutoff amount cost conversion constant data. The contents of these data and the purpose of use will be described later.

Next, the processing of each unit will be described. First, the processing in the generator output adjusting unit 2 will be described.
The rough processing here is as follows. (1) For each generator, the amount of change in the RG index (ΔRGi) when the output is changed by a fixed amount (generator output adjustment range ΔP)
To calculate. (2) When ΔRGi <0, select the generator (Gi) with the largest | ΔRG |. (3) The output of the generator Gi is changed by the adjustment width ΔP.

(4) The above processes (1) to (3) are repeated until there is no generator with ΔRGi <0. (5) When ΔRGi ≧ 0 for all generators, decrease the adjustment width ΔP. (6) The above processes (1) to (5) are repeated until ΔP becomes smaller than the threshold value (generator output adjustment width threshold value δ). (7) When the adjustment width ΔP becomes smaller than the threshold value δ, the process ends.

Next, the detailed processing flow in the generator output adjusting section 2 will be described with reference to the PAD diagram of FIG. (1) The initial value of the initial processing / adjustment width parameter ΔP is read from the parameter database unit 13. Read the initial value of the threshold parameter δ from the parameter database unit 13. -Copies the tidal current data of the grid state database unit 11 to the tidal current data for RG index calculation.

(2) While the adjustment width ΔP ≧ δ, the following (3)
The processing from (17) is repeated. (3) The RG index calculation start signal is output to the RG index calculation unit 3, and the RG index value RG0 data is received. -Calculation of RG index RG0 before generator output adjustment. (4) For all generators subject to adjustment,
The process of is repeated. -Set the selected generator as Gi.

(5) The generator output upper and lower limit data, the fixed supply capacity output data, the transmission line power flow constraint data, and the total demand data are read out from the system state database unit 11, and the output value of the generator Gi is adjusted by ΔP. The value is increased, and the value is added to the fixed supply power output data, and is sent to the tidal current data generation unit 4 with the tidal current constraint to minimize power generation cost, and the tidal current data is received.

The received tidal current data becomes tidal current data when the output value of the generator Gi is increased by the adjustment width ΔP. (6) Update the power flow data for RG index calculation. (7) The RG index calculation start signal is output to the RG index calculation unit 3 and the RG index value RGi ⁺ data is received. -Calculate the RG index RGi ⁺ after adjusting the generator Gi output.

(8) Let ΔRGi ⁺ = RGi ⁺ -RG0. (9) The generator output upper / lower limit data, fixed supply capacity output data, transmission line power flow constraint data, and total demand data are read from the system state database unit 11 and the output value of the generator Gi is Δ.
The value reduced by P is added to the fixed supply power output data, and is sent to the tidal current data generation unit 4 with the tidal current constraint to minimize power generation cost, and the tidal current data is received. The received power flow data becomes the power flow data when the output value of the generator Gi is reduced by the adjustment width ΔP.

(10) Update the tide flow data for RG index calculation. (11) The RG index calculation start signal is output to the RG index calculation unit 3, and the RG index value RGi ^- data is received. And generator Gi output adjusted for RG indicators RGi ^- calculated.

(12) Set ΔRGi ⁻ = RGi ⁻ −RG0.

(13) The minimum value of ΔRGi ⁺ and ΔRGi ⁻ is selected and set as ΔRGi ^x . (14) If ΔRGix ≧ 0, ΔP is updated, and the process returns to (2). -For example, it can be considered that ΔP = ΔP / 2.

(15) If ΔRGi ^x <0, the output of the generator Gi is updated, and the process returns to (2).・ If x = +, the generator output upper / lower limit data, fixed supply capacity output data, transmission line power flow constraint data, and total demand data are read from the system state database unit 11, and the output value of the generator Gi is increased by ΔP. Then, the value is added to the fixed supply power output data and is sent to the power flow cost minimizing power generation cost minimizing power flow data generation unit 4, and the power flow data is received and stored as the power flow data in the system state database.

If x =-, system state database unit 1
From 1, the generator output upper and lower limit data, the fixed supply power output data, the transmission line power flow constraint data, and the total demand data are read, and the value obtained by reducing the output value of the generator Gi by ΔP is set as the fixed supply power output data. In addition, the power generation cost with power flow restriction is sent to the power flow data generation unit 4 to minimize the power flow data, and the power flow data is received and stored as the power flow data in the system state database.

(16) Completion of Generator Output Adjustment / Each generator output value shown in the tidal current data in the system state database is the adjustment result.

Next, the flow of processing in the RG index calculator 3 will be described with reference to the PAD diagram shown in FIG. (1) The following processes (2) to (12) are performed for all the failure cases given by the failure database unit 12. -Set the selected failure case as Fi. (2) If the failure case Fi causes system disruption (3)
(4) to (9) when processing is performed and system division does not occur
Process.

(3) The allowable power loss amount of the frequency lowering side system at the failure point of the failure case Fi is read from the data of the allowable power loss amount of each break point in the system status database unit 11, and from the RG index calculation power flow data. The pre-fault tidal flow rate at the failure point is read out, sent to the load cutoff amount calculation at the time of system disconnection, and the load cutoff amount data at the time of system disconnection is received.

(4) The system configuration data and the RG index calculation power flow data read from the system state database unit 11 are sent to the electronic control unit determination unit 6, and the electronic control unit data is received. (5) Read the output value of the electric control device from the power flow data for RG index calculation, send it to the electric control amount calculation, and receive the electric control amount data. (6) The allowable electric power control amount data and the electric power control amount data read from the system state database unit 11 are sent to the electric load control load shedding amount calculation, and the electric power control load shedding amount data is received.

(7) The generator output upper and lower limit data, fixed supply capacity output data, transmission line power flow constraint data, and total demand data are read from the system state database unit 11 and fixed to 0 for the output of the electric control unit. The power flow data generation unit 4 that adds power output data and minimizes power generation cost with power flow constraint
To receive the current data. (8) Update the tide flow data for RG index calculation.

(9) Each generator output value is read from the RG index calculation power flow data, and the power generation cost characteristic data of each generator is read from the system state database unit 11 and sent to the total power generation cost calculation unit 10 for total power generation. Receive the cost. (10) Add the load shedding amount when the system is divided and the electric system load shedding amount to obtain the load shedding amount. (11) Send the load shedding amount to the load shedding amount cost conversion unit 9,
Receive load shed cost data. (12) The load cutoff cost and the total power generation cost are summed up, and this is multiplied by the weighting factor given to the failure case Fi.・ Set the result as RGi. (13) Add all RGi and use this as the RG index.

Next, the processing of the power flow data generator 4 with the power flow cost with power flow constraint minimized will be described. First, as a process when there is no power flow line constraint at this time, a method using Lagrange's undetermined coefficient method is generally known,
This is disclosed in detail in, for example, Yasuji Sekine and 4 others, "Electrical Power System Engineering", published by Corona Publishing Co., March, 1979.

In this method, the total amount of power generation matches the total demand, and the incremental operating cost of each generator whose output is to be adjusted.
The output of each generator is determined so that (the operating cost required to increase the output by a unit amount while operating at a certain output) becomes equal. Here, if the function of the incremental operating cost is not bounded, such an output value always exists.

However, even in this case, the obtained output value may deviate from the upper and lower limit values of each generator output. And, even in this case, for generators that exceed the upper limit,
The output is set as the upper limit value and excluded from the generators subject to output adjustment, the demand amount obtained by subtracting the generated amount from the total demand and the remaining generators subject to output adjustment are again applied with Lagrange's undetermined coefficient method, By repeating this, the output value considering the upper and lower limits of the output of each generator can be determined.

Also in the present invention, the power generation cost characteristic data given in the system state database gives the operating cost for the output of each generator. Therefore, by using this, the incremental operating cost of each generator is obtained, Lagrange's undetermined coefficient method can be applied.

Therefore, the power flow cost-minimized power flow data generation unit 4 in this embodiment satisfies the given generator output upper / lower limit constraint, fixed supply power output constraint, transmission line power flow constraint, and total demand constraint. The power flow data is generated so that the total power generation cost is minimized. That is, the processing when there is a power flow restriction on the transmission line L of a certain system is as follows.

(1) The generator output that minimizes the total power generation cost is calculated by the equal incremental fuel cost method. (2) Calculate the tidal flow of each transmission line at the obtained output of each generator. (3) If the tidal flow rate of the power transmission line L is less than or equal to the tidal flow constraint, the process ends here, and if not, the process of (4) or less is performed. (4) In the power receiving side system of the power transmission line L, the equal incremental fuel cost method is applied to obtain each generator output, with the total demand = total power generation in the power receiving side system + the power flow constraint excess amount of the power transmission line L.

(5) Total demand in the transmission side system of the transmission line L =
The equal incremental fuel cost method is applied as the total power generation amount in the power transmission side system-the power flow constraint excess amount of the power transmission line L to obtain each generator output.
On the other hand, when there are a plurality of transmission lines with power flow restrictions, all the power flow restrictions are considered by sequentially executing the above processing in accordance with the priority order given in advance.

Next, the processing of the load interruption amount calculation part 5 at the time of system disconnection will be explained. Here, the load interruption amount at the time of system disconnection is the given frequency drop side system allowable power supply dropout amount and the failure point tidal flow before failure. Is calculated by the following formula. Load cutoff amount during system disconnection = Failure point Tide flow rate before failure-Frequency reduction side system allowable power supply dropout amount

Next, the processing in the electronic control device determining section 6 will be described. The electronically controlled machine is a power generator that is electrically controlled.

Here, as a method of determining the electric control device for the failure case Fi, for example, one of the methods is the Institute of Electrical Engineers of Japan, Volume B115, No. 1, January 1995. As described in detail in "Development of system (TSC)", the processing of the electric machine controller 6 according to the embodiment of the present invention also employs this method, and the contents thereof are as follows.

First, assume a failure case for which an electric control machine is to be obtained, and let it be Fi. And the failure case F
The transient stability calculation is performed in the case where there is no electric control device of i, and it is determined whether or not it is stable. If it is stable, it is determined that there is no electric control device for this contingency. Then, if it is unstable, one generator that has the maximum electric control effect is selected from the results of the transient stability calculation. This is the first electric control machine.

Next, at a predetermined timing, the interruption sequence of the previously selected generator is inserted, the transient stability is calculated again, and the stability is judged. And, if stable, the electric control machines currently obtained are all the electric control machines for this contingency.

If it is unstable again, one more generator is considered to have the maximum electric control effect from the result of the transient stability calculation. This is the second electric control machine. Thereafter, this process is repeated until the result of the transient stability calculation becomes stable, so that the electric control device for the failure case Fi can be determined. Once the electric control machine is decided in this way,
As described above, the electric control amount calculation unit 7 sums the output values of these electric control devices to calculate the electric control amount.

Next, the processing in the load shedding amount calculation section 8 during electric control will be described. The load shedding amount under electric control here is calculated by the following formula using the given electric control amount and the allowable electric control amount. Electric load shedding amount = Electric control amount-Allowable electric control amount

Next, the processing in the load cutoff amount cost conversion unit 9 will be described. In the cost conversion of the load shedding amount here, the cost per unit electric energy kWh (load shedding amount cost conversion constant data) preset in the parameter database unit 13 is multiplied by the load shedding amount to obtain the load shedding amount cost. Of.

Next, the processing in the total power generation cost calculation unit 10 will be described. The process here is to obtain the power generation cost for each generator output value by using the given power generation cost characteristic data of each generator, and sum this for all generators to obtain the total power generation cost. This is a calculation process.

Therefore, according to the above-described embodiment, the load cutoff amount and the total power generation cost increase amount at the time of the route disconnection and at the time other than the route disconnection are calculated under the given system state and various constraint conditions to reduce the cost. R, which is calculated by multiplying it by the weighting factor for each failure case and the total power generation cost in normal times
The G index will be obtained.

As described above, this RG index is the sum of the normal total power generation cost and the expected loss loss at the time of cost conversion. Therefore, the smaller this RG index, the more the operation of the power system. Since the cost is low and the cost is taken into consideration, it is an appropriate evaluation index that accurately represents the adequacy of the operation of the power system. Therefore, according to the above embodiment, An accurate evaluation of the power system can be obtained.

As a result, according to the above embodiment,
Since the output of each generator required to minimize this RG index can be calculated, the power system can always be operated in the best condition.

Next, another embodiment of the present invention will be described. The embodiment described below is one in which the present invention is embodied as a power system planning support device, and the degree of improvement of the power system reliability and reduction of the total power generation cost obtained by adding a transmission line are compared with those of the above-described embodiment. Similarly, by using the RG index, which is a feature of the present invention, it is possible to calculate and evaluate in a unified and quantitative manner.

First, FIG. 5 is a functional block diagram of this embodiment. This embodiment is the same as the embodiment of FIG.
5, transmission line extension effect calculation unit 16, system data setting unit 1
7. In addition to the transmission line power flow constraint calculation unit 18, in place of the system state database unit 11, a system database unit before expansion 19, a system database unit after expansion 20, and a system data unit 21 for RG index calculation are provided, Further, the function of the input / output unit 1 and a part of the data content of the parameter database unit 13 are changed, and therefore the other configuration is the same as that of the embodiment of FIG.

The input / output unit 1 has a function of fetching data from the outside (operator or other system) into the power system planning support apparatus and outputting data from the power system planning support apparatus to the outside. Basically, it is the same as the embodiment of FIG. 1, but is specifically different, not only by sending a system start input from the outside to the control unit 2 but also by the system data setting unit 17 In accordance with the instruction signal of, the data about the system before and after the transmission line extension is taken in from the outside and is passed to the system data setting unit 17, and
Transmission line extension effect value ΔRG received via control unit 15
Is output to the outside.

The control unit 15 first receives the transmission line extension effect calculation start signal given by the operator via the input / output unit 1, and firstly, the before-addition system database unit 19 and the after-addition system data unit 19 for the data regarding the system before and after the transmission line extension. Database part 2
0 is instructed to the system data setting unit 17, then a transmission line expansion effect calculation start signal is sent to the transmission line expansion effect calculation unit 16, and the RG before and after the transmission line expansion is set as the transmission line expansion effect value.
The difference ΔRG in the index is received, and this transmission line extension effect value ΔR
It functions to output G to the outside through the input / output unit 1.

The transmission line extension effect calculation unit 16 has two types of RG indicators based on various condition data given from the pre-addition system database unit 19 and various condition data given from the post-addition system database unit 20. The RG index of each kind is calculated by using the RG index calculator 3, and the difference between them is calculated and output as the transmission line extension effect amount. The details of the process will be described later.

Here, the various condition data provided from the pre-expansion system database unit 19 are, as described above, the system configuration data, the initial power flow data, the total demand data,
These are the generator output upper / lower limit data, fixed supply power output data, power generation cost characteristic data, transmission line power flow constraint related data, break point allowable power drop amount data, allowable power control amount data, and power control table data.

The various condition data given from the post-expansion system database section 20 are as described above.
System configuration data and initial power flow data, total demand data, generator output upper / lower limit data, fixed supply capacity output data, power generation cost characteristic data, transmission line power flow constraint related data, break point allowable power loss data, allowable power control data , And electronically controlled table data.

The system data setting unit 17 receives the activation signal from the control unit 15 and executes the following three types of processing (a) to (c). (a) Various data (system configuration data, initial power flow data, total demand data, generator output upper and lower limit data, fixed supply capacity output data,
Power generation cost characteristic data, transmission line power flow restriction related data, break point allowable power supply drop amount data, allowable power control amount data, power control table data) are fetched and stored in the pre-expansion system database unit 19.

(B) Similarly, from the input / output unit 1, various data (system configuration data, initial power flow data, total demand data, generator output upper / lower limit data, fixed supply power output data, power generation cost) related to the system after the transmission line is added. Processing for loading characteristic data, transmission line power flow constraint related data, break point allowable power supply drop amount data, allowable power control amount data, power control table data) and storing it in the system database unit 20 after the expansion.

(C) From the system database section 20 after expansion,
The system configuration data, the initial power flow data, the transmission line power flow constraint related data, the electrical control table data, and each allowable break point allowable power loss amount data are sent to the transmission line power flow constraint calculation unit 18 to recalculate each transmission line power flow constraint related data. A process of receiving the output, the power flow constraint related data of each transmission line, and storing it in the system database unit 19 after the addition.

Next, the transmission line power flow constraint calculation unit 18 determines, based on the given system configuration data, initial power flow data, transmission line power flow constraint-related data, power control table data, and each break point allowable power loss amount data. It recalculates the power flow constraint related data of each power transmission line and outputs it, and at that time, the power flow constraint related data is processed in cooperation with the electronic control device determination unit 6. The details of the processing will be described later.

The pre-addition system database unit 19 manages data necessary for calculating the RG index, such as system state data and various constraint conditions regarding the system before transmission line expansion. Then, in the pre-expansion system database unit 19, as shown in FIG. 6, the system configuration data before the transmission line expansion, initial power flow data, total demand data, generator output upper and lower limit data, fixed supply power output data,
It manages power generation cost characteristic data, transmission line power flow constraint data, break point allowable power supply drop amount data, allowable power control amount data, and power control table data.

The post-expansion system database unit 20 manages the data necessary for calculating the RG index, such as the data regarding the system state and the data regarding various constraints regarding the system after the extension of the transmission line. 1
As in Fig. 9, as shown in Fig. 6, system configuration data after transmission line expansion, initial power flow data, total demand data, generator output upper / lower limit data, fixed supply capacity output data, power generation cost characteristic data, transmission line power flow constraint It manages related data, break point allowable power supply drop amount data, allowable power control amount data, and power control table data.

Here, these database units 19 and 20
The details of the data managed by are as follows. The system configuration data is each constant of system equipment such as impedance of a transmission line and rated capacity of a generator, and connection information between each system equipment. The initial power flow data is an initial value of electrical data (active power, reactive power, voltage, etc.) on each system equipment such as a generator, a load, and a transmission line. The total demand data is a value obtained by summing active powers of all loads.

The generator output upper and lower limit data is the upper and lower limit values of the active power output given to each generator. Fixed power output data is data that specifies active power output values for some generators. The power generation cost characteristic data is data that gives the power generation cost of each generator according to the output.

The transmission line power flow constraint related data is data which gives the upper limit of the active power flow rate of each transmission line,
The heat capacity surface power flow constraint data, the frequency surface power flow constraint data, and the stability surface power flow constraint data are three types of data, and the transmission line power flow constraint data defined by the minimum value thereof.

Separation point Allowable power supply dropout amount data refers to a point where a system is divided, and occurs when the point is divided.
It is the data that gives the allowable upper limit of the amount of power generation insufficiency for each divided system. The allowable electricity control amount data is data that gives the upper limit value of the amount of power generation insufficiency that is allowable in the entire system.

The electronically controlled table data is the electrically controlled starting condition data including the failure point / failure content and the failure point tide flow rate threshold value,
On the other hand, the electric machine data is made to correspond, and the failure content is data representing a one-line accident, a three-phase four-wire ground fault, etc., and the failure point tide flow rate threshold is the actual failure point tide flow rate. Is the standard value that the electronic control is implemented when the value exceeds that value.

The RG index calculation system data section 21 is
Regarding the target system for which the index is calculated, system configuration data, initial power flow data, total demand data, generator output upper and lower limit data, fixed supply capacity output data, power generation cost characteristic data, transmission line power flow constraint data, break point allowable power loss It manages data, allowable power control data, and power control table data.

Among the data managed by the parameter database unit 13, the load cutoff amount cost conversion constant data is the same as that in the embodiment of FIG. 1, but the other data is the transmission line tide flow rate adjustment width data. It is different in that it has become. The other blocks are the same as those in the embodiment shown in FIG. 1 and therefore will not be described.

Next, the processing by the transmission line extension effect calculation unit 16 will be described with reference to the PAD diagram shown in FIG. (1) Copy the data of the pre-expansion system database section 14 to the RG index calculation system data section 21. (2) The generator output upper / lower limit data, fixed supply capacity output data, transmission line power flow constraint data, and total demand data are read from the RG index calculation system data unit 21, respectively, and the power flow cost with power flow constraint minimizes the power flow data generation unit. 4 and then receive the tidal current data.

(3) Update the data of the RG index calculation power flow data section 14 with the received power flow data. (4) The RG index calculation start signal is output to the RG index calculation unit 3, and the RG index value RG0 data is received therefrom. (5) Copy the data of the system database section 20 after the expansion to the system data section 21 for RG index calculation. (6) The generator output upper and lower limit data, the fixed supply capacity output data, the transmission line power flow constraint data, and the total demand data are read from the RG index calculation system data unit 21, respectively, and the power generation cost minimized power flow data generator with the power flow constraint is read. 4 and then receive the tidal current data.

(7) According to the received power flow data, RG
The index calculation power flow data unit 14 is updated. (8) The RG index calculation start signal is output to the RG index calculation unit 4, and the RG index value RG1 data is received therefrom. (9) Set ΔRG = RG1-RG0. (10) This ΔRG is output as the transmission line extension effect amount. Here, the RG index processing by the RG index calculation unit 3 is as already described with reference to the PAD diagram shown in FIG. 4 in the embodiment of FIG.

Next, the processing by the transmission line power flow constraint calculation unit 18 will be described with reference to the PAD diagram shown in FIG. In the embodiment of FIG. 1, the transmission line power flow restriction data is stored in advance in the system state database unit 11 as a constant, but in the embodiment of FIG. 5, since it is premised on the addition of transmission lines, it is given as a constant. I can't. Therefore, in the embodiment of FIG. 5, the transmission line power flow constraint calculation unit 1
8, the transmission line power flow constraint data is given in the following manner.

(1) Initial processing / system configuration data, power flow data, transmission line power flow constraint-related data, power control table data, and each break point allowable power supply drop amount data are received. The power flow adjustment width data of the power transmission line is read from the parameter database unit 13 and is set as ΔP.・ P = −ΔP.

(2) For all transmission lines Li,
Perform steps (3) to (9). (3) The processes (4) to (7) are performed until there is an unstabilizable failure case where the transmission line Li is the failure point. (4) P = P + ΔP. (5) A load of + P is additionally installed at the power receiving side node of the power transmission line Li in the given power flow data, and a load of −P is additionally installed at the power transmitting side node. -Increase the tidal flow rate PLi of the power transmission line Li by P.

(6) For all the failure cases where the transmission line Li given by the failure database unit 12 is the failure point,
Perform the processing of (7). -Set the selected failure case as Fj.

(7) The data of the failure case Fj, the given system configuration data, the given electric control table data, and the tidal current data corrected by the processing of (5) are sent to the electric control device deciding unit 6. Send and obtain the result of whether stabilization is possible by the electric control of the decided electric control machine.

(8) Let P-ΔP be the stability surface power flow constraint value PLi ³ of the transmission line Li. (9) The heat capacity surface flow constraint data PLi ¹ of the transmission line Li is
The data is read from the given power line constraint data. (10) If the power transmission line Li forms a part of the loop system, the process of (11) is performed, and if not, the process of (12) is performed.

(11) Frequency plane power flow constraint value P of transmission line Li
Li ² is set as max {PLi ¹ , PLi ³ }. (12) From the given data on the allowable amount of power loss for each break point,
The permissible power dropout amount of the frequency lowering system of the power transmission line Li is read out, and this is read as the frequency plane power flow constraint value PLi ^{3 of the} power transmission line Li.
And (13) Set the power flow constraint value PLi of each transmission line Li to min {PLi
¹ , PLi ² , PLi ³ }.

(14) PLi ¹ is heat capacity surface flow restriction data of each transmission line Li, PLi ² is frequency surface flow restriction data,
PLi ³ is set as the stability surface power flow constraint data, and PLi is set as the transmission line power flow constraint data, and each is output from the system data setting unit 17 to the data units 19 and 20.

Therefore, according to this embodiment, the transmission line extension effect value ΔRG, which is the difference between the RG indices before and after the transmission line extension, can be easily obtained from the input / output unit 1 at any time by the operator's instruction. As a result, the operator evaluates the transmission line extension effect value ΔRG to accurately determine the effect of the transmission line extension on reliability and economic efficiency under a quantitative and uniform index. Can be determined.

[0113]

According to the present invention, the loss at the time of failure at the time of the route disconnection and the time at the time of other than the route disconnection are cost-converted, weighted for each failure case and summed, and this and the total power generation cost at normal times are summed. The reliability and economic efficiency, which are probabilistic concepts, can be quantitatively evaluated with a unified index of costs, depending on the magnitude of the RG index obtained.

Further, the RG index is calculated for each of the power systems before and after the transmission line is added, and the difference is calculated to quantitatively unify the effect of the transmission line addition on reliability and economy. It can be evaluated with various indicators.
Further, at this time, by recalculating the power flow constraint of each transmission line in the system after the transmission line is added, it is possible to more accurately obtain an evaluation of the total amount of power generation cost improvement by the generator output redistribution due to the addition of the transmission line. .

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of various data used as a database in the first embodiment.

FIG. 3 is an explanatory diagram of a processing flow in a generator output adjustment unit according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram of a processing flow in an RG index calculation unit in the embodiment of the present invention.

FIG. 5 is a functional block diagram showing a second embodiment of the present invention.

FIG. 6 is an explanatory diagram of various data used as a database in the second embodiment of the present invention.

FIG. 7 is an explanatory diagram of a processing flow in a transmission line extension effect calculation unit according to the second embodiment of the present invention.

FIG. 8 is an explanatory diagram of a processing flow in a transmission line power flow constraint calculation unit in the second embodiment of the present invention.

[Explanation of symbols] 1 I / O section 2 control unit 3 RG index calculator 4 Power flow cost generation with power flow constraint to minimize power generation cost 5 Load cut-off amount calculation section for system disconnect 6 Electric control machine decision part 7 Electricity calculation section 8 Load shedding calculation section under electric control 9 Load cutoff cost conversion unit 10 Total power generation cost calculator 11 System status database section 12 Failure database section 13 Parameter database section 14 Power flow data section for RC index calculation 15 Control unit 16 Transmission line expansion effect calculation unit 17 System data setting section 18 Transmission line power flow constraint calculation unit 19 System database before expansion 20 System database after expansion 21 RG index calculation system data section

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Tamura 5-2-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Omika factory (72) Inventor Shikao Tanaka 3-chome Nakanoshima, Kita-ku, Osaka-shi, Osaka 3-22 Kansai Electric Power Co., Inc. (72) Inventor Shinobu Inoue 3-3-22 Nakanoshima, Kita-ku, Osaka-shi, Osaka Kansai Electric Power Co., Inc. (56) Reference JP-A-4-54828 (JP, A) JP-A-8-196041 (JP, A) JP-A-62-155728 (JP, A) JP-A-61-210830 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02J 3/00-5/00 H02J 13/00-13/00 311

Claims (6)

(57) [Claims] 1. A means for calculating a load shedding amount at the time of a route disconnection failure, a means for calculating a load shedding amount due to a forced generator shutdown at the time of a failure other than a route disconnection, and a means for converting the load shedding amount into a cost. The means for calculating the amount of change in the total power generation cost due to forced shutdown of the generator at the time of failure, the load cutoff cost at the time of failure, and the total amount of power generation cost change are added together, and this is added by the weighting factor for each failure case. An electric power system evaluation device comprising: a failure loss cost means; and a means for adding the failure loss cost and the normal total power generation cost and outputting the cost as an evaluation index. 2. The load cutoff amount cost obtained by converting the total load cutoff amount at the time of a route cutoff fault and the load cutoff amount at the time of a fault other than the route cutoff by the generator forced cutoff to a cost,
The value obtained by summing the change amount of the total power generation cost due to the forced shutoff of the generator is set as the loss cost at the time of failure, and this loss cost at the time of failure is added up by the weighting factor given to each failure case, which is A method for optimizing a power system power flow, comprising summing the total power generation cost to obtain a power system evaluation index, and controlling the generator output so that the evaluation index is minimized. 3. A means for calculating a load shedding amount at the time of a route disconnection failure, a means for calculating a load shedding amount due to a forced generator shutdown at the time of a failure other than a route disconnection, and a means for converting the load shedding amount into a cost. The means for calculating the amount of change in the total power generation cost due to forced shutdown of the generator at the time of failure, the load cutoff cost at the time of failure, and the total amount of power generation cost change are added together, and this is added by the weighting factor for each failure case. Calculates the loss cost at the time of failure, the means for adding the loss cost at the time of failure and the total power generation cost in normal times, and outputting it as an evaluation index, and the output of each generator required to minimize this evaluation index. A power system power flow optimizing device comprising: 4. The electric power supply system according to claim 1 , further comprising: a means for providing a current failure occurrence probability as a weighting factor for the failure case online, and a means for fetching a current system state online. System evaluation device. 5. The electric power supply system according to claim 3 , further comprising: a means for providing a current failure occurrence probability online as a weighting factor for the failure case and a means for capturing a current system state online. System power flow optimization device. 6. A power system planning support apparatus for evaluating the improvement effect of reliability and economy by adding a transmission line of a power system, a means for calculating a load shedding amount at the time of a route disconnection failure, and a means for calculating a load disconnection amount at the time of a route disconnection failure. A means for calculating a load shedding amount due to the forced shutoff of the generator; a means for converting the load shedding amount into a cost;
The means for calculating the amount of change in the total power generation cost due to forced shutdown of the generator at the time of failure, the load cut-off cost at the time of failure, and the total amount of power generation cost change are added together, and this is added by the weighting factor for each failure case. There are means for calculating the loss cost at the time of failure, means for adding the loss cost at the time of failure and the total power generation cost for normal operation, and outputting as an evaluation index, and means for calculating the power flow constraint value of each transmission line in the system after the transmission line is added. And a means for calculating the difference between the power system evaluation indexes of the system before and after the transmission line extension by using each of the above means.