JPS6117219B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a control device for a power receiving/distributing system having private power generation equipment. Conventionally, in general industrial power receiving and distribution systems, in-house power generation equipment is often installed as an emergency power source in case of a power outage. This private power generation equipment is activated immediately when the purchased electricity is out of power and supplies electricity to the necessary load. However, considering the stable supply of electricity, with the above equipment, one or all of the loads will inevitably experience a power outage, and even very important loads cannot avoid instantaneous power outages.
Possible countermeasures include operating a constant-voltage, constant-frequency power source (hereinafter referred to as CVCF) or constantly operating private power generation equipment in parallel with the power purchasing equipment. However, such constant operation of CVCF or private power generation is uneconomical in terms of equipment and usage costs. On the other hand, the power to purchase electricity is, of course, based on the electricity supplied by the electric power company, but this supplied electricity is not unlimited, and each contract has a certain limit value. According to this contract, for a certain period of time, for example, 15 minutes,
The load capacity used must be adjusted from time to time so that the power used within a period of 30 minutes does not exceed this upper limit. This is called demand monitoring or demand control. This demand monitoring method involves predicting the power consumption after the demand cycle is reached at the power sampling point within the demand cycle, and then checking the power consumption at the sampling point (for example, every minute) so that this predicted value does not exceed the contracted power. There is an example in which a load with a lower rank is selected or rejected based on the importance class assigned to the load. However, although it is of low importance, it is not preferable from the standpoint of load operation to interrupt the load during operation, and it is preferable not to interrupt the load during operation as much as possible. The purpose of the present invention is to predict over-demand in a power receiving/distribution system having private power generation equipment, in particular, to reduce load interruptions and interruptions during operation by having private power generation equipment bear part of the load group. An object of the present invention is to provide a control device for a power receiving and distribution system that partially enables uninterrupted switching during a power outage. The present invention will be described below with reference to an embodiment shown in the drawings. In FIG. 1, purchased power is supplied from a cable head 5 to a load bus through a power company's commercial instrument transformer 4, a power receiving disconnector 3, and a power receiving disconnector _C1 . Each load L ₁ , L ₂ , . . . Ln is connected to the bus bar via a load feeder or a disconnector F ₁ , F ₂ , . . . Fn. The above-mentioned busbar is divided into each of the above-mentioned loads L ₁ , L ₂ ...Ln by providing a plurality of busbar connecting and disconnecting switches B ₁ , B ₂ ...Bn _-1 . The more important the loads L ₁ , L _{2 , . .} . Ln are connected to the bus section on the right side of the diagram. GEN is a private power generation facility, with multiple (m) generators GEN ₁ , GEN ₂ ,...
GENm, respectively for generator use and disconnection G ₁ ,
G ₂ ,...Gm are provided, and are further connected to the right end of the bus bar via a breaker C ₂ . In Fig. 1, the purchased power and privately generated voltage are supplied from the instrument transformers PT ₁ and PT ₂ , and the purchased power, privately generated and each load feeder current are supplied from the current transformers CT ₁ , CT ₂ , and CTL ₁ , CTL ₂ ,...
The data is obtained from CTLn, and the power at various locations is measured using a power transducer (not shown), etc., and is used as process data when making demand predictions. For such systems, control devices for performing demand control and switching control during power outages are shown in Figures 2 to 7.
This will be explained using figures. FIG. 2 is a flowchart showing a control process that is repeated at regular intervals, and will be explained below. First, in step 2a, disconnect each side.
Their states are stored using open/close state signals from _C1 , _C2 , , _B1 to Bn, _G1 to Gn, and _F1 to Fn. Next, in step 2b, transform the voltage transformer shown in Figure 1.
Various amounts of electricity are input and stored from PT ₁ , current transformer CT ₁ , CT _L1 to CT _Lo , etc. In step 2C, the purchased power is calculated from the above various data and the demand is predicted. If a power shortage is detected up to the above-mentioned demand cycle (in 15-minute or 30-minute units), the corresponding demand power generation amount is calculated. do. Based on this demand power generation request amount, a power generation request amount during a power outage is calculated in step 2d. Of course, when there is no power outage, the demand power generation amount is used as is.
Based on these required amounts of power generation, the corresponding generators are activated and controlled in step 2e. In step 2f, system switching control is performed in accordance with the generator operating capacity. In step 2g, when the power demand decreases and the operating capacity of the generator is too large, the generator corresponding to the excess capacity is controlled to be stopped. In step 2h, time delay control is performed to obtain a constant control cycle, and the process returns to step 2a to repeat the same control process. Next, the main parts of the above control process will be explained in detail. The calculation of the demand power generation amount in step 2c of FIG. 2 is performed according to the flowchart shown in FIG. As mentioned above, step 2b in FIG.
The demand shortage power P _R is calculated in step 3 by various analog signal inputs (voltage, current) input in
Calculated at a. This calculation method is well known in the normal demand method, and its detailed explanation will be omitted. Next, this demand power shortage P _R is replaced with the predetermined capacities of the loads L ₁ to Ln shown in FIG. That is, first, in step 3b, it is determined whether P _R >0, and if NO, the demand insufficient power P _R is replaced with 0 in step 3c. P _R >0
If YES, proceed to step 3d and apply the load here.
Compare P _R > P _L1 with the capacity value PL ₁ of L ₁ , and if NO, replace the demand insufficient power P _R with the load capacity PL ₁ in step 3e. If P _R > _PL1 is YES, proceed to step 3f and perform a similar comparison. In this way, sequential comparisons are made and the demand shortage power P
If you proceed to step 3x due to the size of _R ,

If [Formula] is YES, the demand power generation request amount remains the value of the initially determined demand power shortage P _R . Next, we will explain the calculation of the required amount of power generation during a power outage (step 2d in Figure 2) using the flowchart in Figure 4.Before that, we will explain the state during normal operation and when a power outage occurs using Figure 5. , the symbols used in FIG. 4 will be explained. In Figure 5, t ₁ to t ₁₅ are the second
It represents the time at which the control process shown in the figure is executed. P
_J is the purchased power supplied from the power company, and the load L ₁
~ Varies depending on the operating status of Ln. When the operating capacity of the load increases and a demand power shortage P _R (represented with a time suffix in the figure) occurs, as from time t ₆ to _{t 9} , this amount is reduced to the first power by the effect described later. The burden will be borne by the privately generated GEN shown in the figure. In this case, the sum of the purchased power P _J (time stamps are added in the figure) and the demand shortage power P _R (borne by private generation GEN) is:
The currently used power is P _G '. If a power outage has not occurred, as will be described later with reference to FIG. 4, the demand power shortage P _R becomes the current power generation request data P _G as it is. Returning to FIG. 4, in calculating the required amount of power generation during a power outage, first, in step 4a, use the data from the previous control, for example, if the current control is set to time _t9 in FIG. The data used as the power generation request data P _G at _{time t 8} is replaced with the previous data PH, and the current power generation request data P _G at time _t9 is set to 0.
Replace with Next, in step 4b, it is determined whether there is a power purchase power outage or not, that is, P _J =0? Find out. If NO, that is, there is no power outage, the process proceeds to step 4c, where the demand power generation request amount P _R obtained in the flowchart of FIG. 3 is replaced with the current power generation request data P _G. The power generation request data _PG is used to start and control a generator, which will be described later, but the currently used power _PG ' is stored in case a power outage occurs during the next control. That is, in step 4d, it is checked whether the above-mentioned demand power generation request amount P _R is P _R ≠ 0, and if no, in step 4e, the purchased power P _J is replaced with the currently used power P _G
If YES, the sum of the purchased power P _J and the requested power generation amount P _R is replaced with the currently used power in step 4f. Next, the case where it is determined in step 4b that there is a power purchase power outage will be explained. The control time at this time is _t10 in FIG. That is, when it is determined in step 4b that a power outage has occurred, the current power used at time _t9 , which is replaced by step 4e or 4f at the previous control time t9, is changed to the current _power used at time _t9 , that is,
P _J t ₉ +P _R t ₉ is replaced with the required power generation amount P _G at time t ₁₀ in step 4g. Based on the above-mentioned power generation request amount P _G , the start-up control of the generator of the corresponding capacity is performed according to the flowchart shown in FIG. (Corresponding to step 2e in FIG. 2) That is, in step 6a in FIG. 6, the current power generation request data _PG is compared with the previous power generation request data _{PH .}
>Perform P _H. For example, at control time _t9 , there is no power outage, so as shown in step 4c in Fig. 4, the current power generation request data P _G is P _R t ₉ , and similarly, the previous power generation request data P _H is P _R t ₈ . be. and P _G > P _H
If is NO, the generator start control is not performed and the program proceeds to the next program. On the other hand, P _G > P _H
If YES, the number of operating generators to satisfy the current power generation request amount P _G is determined in step 6b, and a start command is output to the corresponding generator in step 6c. On the other hand, if a power outage occurs, for example at control time _t10 , as shown in step 4g in Figure 4,
As the power generation request data P _G at t ₁₀ , the current power used P _G ' of the previous time t ₉ , that is, in this case, P _J t ₉ +P _R t ₉ is used. Further, as is clear from step 4a, P _H uses the power generation request data P _G at the previous time t ₉ , that is, in this case, P _R t ₉ . Therefore, a state of P _G >P _H is always established, and starting control of the corresponding generator is performed in steps 6b and 6c in order to satisfy the current power consumption P _G at time _t9 . Next, according to the flowchart in FIG. 7, system switching control is performed in accordance with the above-mentioned generator starting capacity.
(Corresponds to step 2f in Figure 2) First, step 7
In step a, the capacity P _S that can be transmitted by the private generator GEN is calculated from the activated generators and their respective power generation capacities. This power transmission capacity P _S is sequentially compared with the integrated capacity of each load L ₁ to Ln shown in FIG. That is, in step 7b, it is compared with the capacity P _L1 of the load L ₁ to determine whether P _S >P _L1 . And if NO,
Proceed to the next program without switching. If YES, the process proceeds to step 7c, where it is determined whether P _S >P _L1 +P _L2 . If NO, then in step 7d, the opening and closing of the shield breakers C ₂ and B ₁ shown in FIG. 1 is controlled so that up to the load L ₁ is connected to the private generator GEN side system. The opening/closing order of the shingle breaker C ₂ and B ₁ is as follows: First, the shingle breaker C ₂ is turned on, and then the shingle breaker B ₁ is opened.
At this time, if the power purchasing side is in good condition, the private power generator GEN performs instantaneous parallel operation with the power purchasing side, and then independently supplies power to the load L ₁ by opening the disconnector B ₁ .
In other words, the load _L1 is switched to the private power generation side without power outage. On the other hand, in step 7c, P _S > P _L1 + P _L
2 If YES, then the load capacity is further added and compared sequentially at the upper step. and home run
If the power transmission capacity P _S of GEN is

If [Formula] is determined to be YES, a control signal is issued in step 7z so that the entire load L ₁ to Ln is switched from the power purchasing side to the private generation GEN side system. The above operation is exactly the same for both demand adjustment during non-power outages and power supply switching during power outages. FIG. 8 is a flowchart for stopping a surplus generator based on demand prediction, and corresponds to step 2g in FIG. 2. That is, the current power generation request data P _G obtained in FIG.
A is compared with the previous power generation request data P _H. If _PG < _PH is NO, proceed to the next program, but if _PG < _PH is YES, the number of operating units is determined in step 8b to satisfy the current power generation request data _PG , and the result is Step 8 with the leftover generator
Stop control is performed at c. Next, to explain the overall operation, normally, the shield disconnectors C ₁ , B ₁ to B _o-1 in Fig. 1 are inserted,
The circuit breakers C ₂ , G ₁ to Gm on the private generator GEN side are left open, and the power is operated only by the power purchasing side system. In this state, when the operating capacity of the loads L ₁ to Ln increases and a demand power shortage P _R occurs as shown at times t ₆ to _{t 9 in} FIG. ₅ , the above-mentioned Obtain demand power generation request data P _G using Frochaert,
The generators GEN ₁ to GENm corresponding to this are activated as appropriate. When the generator is started, its power generation capacity P _S and load capacity P _L1 to P _Lo are compared, and if power transmission is possible,
The load corresponding to the power transmission capacity P _S is sequentially switched to the private power generation side starting from the one on the right side of the figure, that is, the load _L1 . In this case, as described above, the load is switched uninterrupted. In this state, for example, if a power outage occurs on the power purchasing side between times _t9 and _t10 in FIG. 5, the power purchasing side system will of course be in a power outage state. However, due to the demand control, the load that has been switched to the private generation GEN side continues to operate. Therefore, if you place the most important load L ₁ on the right end of the diagram, and arrange the loads L ₂ to Ln on the left side so that their importance decreases, the most important load during demand control will be Since switching is controlled by the grid, important loads can continue to operate without interruption even if a power outage occurs. After the power outage is restored, the power purchasing side and the private generation side will operate in parallel, resulting in a surplus generator on the private side.
In this case, the surplus generator may be stopped using the program shown in FIG. Another embodiment of the invention is shown in FIG. In Figure 9, bus ₁ is used as a bus only for the power purchasing system,
On the other hand, a new bus ₂ for each generator is installed, and each load L ₁ to _Ln is connected to both buses ₁ and ₂ through mustard disconnectors F ₁ to Fn and mustard disconnectors F _G1 to F _Go . Connecting. With this configuration, it is possible to switch to the private power system in order of importance by specifying it on the control program, without considering the order of load importance as an arrangement on the system. , can be said to be more advantageous than the system configuration shown in FIG. As described above, according to the present invention, the amount of power generation requested by demand monitoring and the amount of power generation requested at the time of a purchased power outage can be smoothly switched by detecting a power purchased power outage, and it is possible to smoothly Since the loads are connected sequentially starting from the generator side, the load that has already been switched to the generator side due to demand control will not experience a momentary power outage even during a power outage. Including the advantage of being able to avoid the load loss, it is possible to maintain a certain transition pattern without having to reorganize, such as by once disconnecting all the disconnectors and then connecting only the necessary loads. , which will be successively connected to the generator system. Therefore, if a power purchase power outage occurs during demand control, it is actually more preferable than when the entire load is connected to the power purchase.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a power reception and distribution system to which the device of the present invention is applied, and FIG. 2 is a flowchart illustrating an embodiment of the power reception and distribution system control device according to the present invention.
3 to 8 are flowcharts explaining the details of each control step shown in FIG. 2, and FIG. 9 is a system diagram showing another example of the power receiving and distribution system. GEN...Private power generation equipment, _C1 ...Power receiving side disconnector, _L1 -Ln...Load, 2a-2h...Overall control step, 3a-3g...Step for calculating demand power generation amount, 4a-4g... Steps for calculating required amount of power generation during power outage, 6a to 6c... Control steps for generator startup, 7a to 7z... Steps for system switching control, 8a
~8c... Control step for stopping the generator.

Claims (1)

[Scope of Claims] 1. In a control device for a power receiving and distribution system that has a power purchasing system and a private power generation system, is capable of supplying power to loads from both of these systems, and always supplies power to the loads from the power purchasing system, A demand power generation request calculation means inputs the purchased power P _J every cycle and calculates the demand insufficient power P _R that will be insufficient to maintain the contracted power from now on; If it is determined that there is no power outage, the demand power shortage P _R is set as the current power generation request data P _G and the current power usage P _G ' is memorized, and in the case of a power outage, the current power usage P _G ' in the previous cycle is stored. The power _generation request amount calculation means at the time of a power outage, which is _the current power generation request _{data P}
> P _H , a generator output increasing means for increasing the output of the private generator to satisfy the current power generation request _{data P} A control device for a power receiving and distribution system, comprising: system switching output means for switching the system so that a load with a high priority corresponding to P _S is supplied with power by a private generator;