JPH0799909B2 - Parallel operation device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a parallel motion device in which a plurality of generators are synchronously input, and after parallel insertion, the load is shared.

[Prior Art] As a conventional technology, there is a synchronization input device shown in FIG. 3 and a load sharing device shown in FIG.

FIG. 3 shows a conventional synchronous loading device, and in the figure, 1a, 1
b is a generator, 2a and 2b are prime movers for driving these generators 1a and 1b, 3a and 3b are circuit breakers for generators, 4 is a circuit breaker for busbar communication, 5
a and 5b are loads connected to the generators 1a and 1b through the generator breakers 3a and 3b, 6a and 6b are analog / digital conversion circuits,
7 is an arithmetic circuit for confirming the establishment of the voltage of the generators 1a, 1b, 8
Is based on the calculation result, the circuit breakers 3a, 3b, 4 are turned on and off and the generator 1a,
It is an output circuit that outputs adjustment signals for 1b and the prime movers 2a, 2b.

Fig. 4 shows a conventional load sharing device.
9a and 9b are active power detectors of the generators 1a and 1b, 10 is an averaging circuit for obtaining average active power per unit, 11a and 11b are generators 1a and 1b, respectively.
Active power detector 9a 1b, the active power V _a of 9b, V _b and the average circuit 10
Of the prime mover 2a, 2b according to the deviation.
Is an operational amplifier circuit that outputs the adjustment signal of.

Next, the operation will be described. In FIG. 3, for example, if the generator 1a side is in operation and the generator circuit breaker 3a and the busbar communication circuit breaker 4 have already been closed, the second generator 1b is started and the generator circuit breaker is activated. When inputting 3b, synchronous input is required. In this case, first, the voltage establishment of the generator 1a during power supply is confirmed by the arithmetic circuit 7 through the analog-digital conversion circuit 6a, and if established, the voltage of the input side generator 1b
The frequency is adjusted to the voltage / frequency of the generator 1a on the receiving side by the arithmetic circuit 7 which is also input through the analog / digital conversion circuit 6b. If the difference between these voltages and frequencies falls within the allowable value, then the voltage phases of the two machines are compared, and the closing signal of the generator circuit breaker 3b is output through the output circuit 8 at the phase matching point. When the synchronous closing is completed, the load is shared, but in FIG. 4, the load sharing of the two generators 1a and 1b is to first detect the active powers V _a and V _b of both generators by the active power detectors 9a and 9b, The averaging circuit 10 finds the set power that each unit should bear. For simplicity, if the capacities of both units are the same, the set power V _M in the averaging circuit 10 will be 1/2 of the total detected power V _a and V _b of both units. Next, if there is a difference between the set power V _M and the detected power V _a or V _b , the operational amplifier circuits 11a and 11b are controlled so that this deviation becomes zero. That is, the deviation from the set power for generators a and b For example, when the active power V _a of the machine _a is larger than the active power V _{b of the} machine b, the deviation of the machine a is plus and the deviation of the machine b is minus, and a lowering adjustment signal is sent to the machine a prime mover 2a to the machine b 2b. A raising adjustment signal is output.

With such a configuration, the active powers V _a and V _b of the generators 1a and 1b are averaged, that is, shared among the capacity ratios.

Thus, as a conventional example of the synchronizing input device, there is Japanese Patent Laid-Open No. 55-10.
It is shown in Japanese Patent Publication No. 9135 and Japanese Patent Publication No. 36493/1984 as a conventional example of the load sharing device.

[Problems to be Solved by the Invention]

As described above, the conventional parallel operation device is composed of one synchronous loading device and one load sharing device. Therefore, if the synchronous loading device or the load sharing device fails, parallel operation becomes impossible. If a malfunction occurs due to a failure of the load sharing device during parallel operation, the load sharing becomes abnormal, resulting in overload or reverse power, and the generator protection device separately equipped trips the generator, causing a serious accident such as loss of power. It can be. Further, the conventional parallel operation device has a problem that the input / output signal line needs to be switched every time the configuration of the generators operating in parallel changes. Furthermore, when generators that are operated in parallel are installed separately in different sections, the number of signal lines for digital input, analog output, digital output, etc. between sections becomes long and large, and disconnection or short circuit of these signal lines may occur. The probability of an accident increases. Therefore, when a disconnection or short circuit occurs, the parallel operation device executes control of load sharing etc. with incorrect input data, resulting in abnormal imbalance and generator overload or reverse power, tripping the generator in the same manner as above. Then, there is a problem that there is a risk of parallel operation failure and power supply stop.

The present invention has been made to solve the above-mentioned problems, and a parallel operation device is provided for a generator so that the generator can be operated in parallel and switching input / output signals at the time of change can be facilitated. And an accident diagnosis function that detects abnormalities during load sharing control and short-circuits / disconnections of signal lines, and the automatic synchronization input function and load sharing required for parallel operation even when the above-mentioned control abnormalities, disconnections or short circuits occur. It is an object of the present invention to obtain a parallel operation device capable of maintaining the function and short-circuiting and reducing the number of signal lines between sections.

[Means for Solving the Problems]

The parallel operation device according to the present invention is a generator voltage / frequency /
Detection circuit that detects analog data of active power / reactive power, voltage difference / frequency difference / phase difference of both generators at the time of synchronous input, and active power / reactive power of bus connecting line, and analog to convert these analog data to digital An input circuit, an arithmetic circuit that receives outputs from the analog input circuit and performs arithmetic necessary for synchronous closing and parallel operation, and an output circuit that outputs a signal for driving the generator / motor based on the arithmetic result of the arithmetic circuit And a self-diagnosis circuit that detects an abnormality in each of these circuits.

[Action]

The parallel operation device in this invention performs the synchronous closing control as a constant voltage / constant frequency control by the generator control device corresponding to the injection target side, and only the corresponding generator is controlled by the control device side which is in charge of the circuit breaker closing control. Control is performed so that the voltage difference and frequency difference between both power supply stations are kept within specified values, and then the synchronization point is calculated and the circuit breaker is turned on at that point. When the analog input data is exchanged with each other, the load is shared according to the rated capacity, and when the self-diagnosis circuit detects an abnormality, the fault side power supply station maintains the reference voltage and reference frequency, and the normal side power supply station The load is shared by controlling the active / reactive power of the busbar connecting line to zero.

Example of Invention

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.
In the figure, the same components as those in FIG. In addition, since the power feeding station is classified according to the generator and the load, in the case of the present embodiment having two power feeding points, a and b are associated with a power feeding station and b power station.
The subscript of is added to the code.

In Fig. 1, 7a and 7b are the voltage differences during synchronous closing side control.
Calculation to perform necessary operations for synchronous loading and load sharing based on analog data such as frequency difference / phase difference, voltage / frequency of generators 1a, 1b, active power, reactive power, and active power / reactive power of bus line This is a circuit, and the arithmetic circuits 7a and 7b are connected to each other by one digital communication line 100. 8
a, 8b receives the calculation results of the calculation circuits 7a, 7b, generators 1a, 1b,
Output circuits that output drive signals to the prime movers 2a, 2b and circuit breakers 3a, 3b, 4a, 4b, and 12a, 12b are voltage differences and frequency differences that detect the voltage difference, frequency difference, and phase difference required for synchronous closing control.・ Input switching circuit that switches the input to the phase difference detection circuit 13a, 13b to the target circuit breaker side by the output of the arithmetic circuit 7a, 7b according to the synchronous closing command, 14a, 14b are the voltage difference / frequency difference / phase difference detection circuit In addition to 13a, 13b, the active / reactive power detection circuits 15a, 15b of the generators 1a, 1b and the voltage / frequency detection circuits 16a, 16b, and the active / reactive power detection circuits 17a, 17b for busbar communication lines are received and digitalized. Analog input circuit to convert to signal,
18a, 18b are the various detection circuits 13a, 13b, 15a, 15b, 16a, 16b, 1
7a, 17b and analog input circuits 14a, 14b, arithmetic circuits 7a, 7b, output circuits 8a, 8b, and abnormalities in data communication signals between the two units are detected, and reference voltage setting circuits 19a, 19b and reference frequency setting circuit 2 are detected.
Self-diagnosis circuits that output signals to 0a and 20b, 21a and 21b are parallel operation devices, and 22a and 22b are power supply stations divided corresponding to loads 5a and 5b and generators 1a and 1b.

Next, the operation will be described with reference to the flowchart shown in FIG. The parallel operation device is equipped with a synchronous loading function and a load sharing function for each generator. Now, in the case of two generators, when the parallel operation devices 21a and 21b are normal, input by the parallel operation command of step ST1 according to the flowchart shown in FIG. 2 (a) and by the output of the arithmetic circuit 7a or 7b in step ST2. The switching circuit 12a or 12b is connected to the circuit breaker 3a or
Switch to 3b or 4a or 4b side.

Then, in step ST3, the generator breaker 3a or 3
The voltage difference, the frequency difference and the phase difference between both ends of b and the busbar breakers 4a and 4b are the voltage difference, the frequency difference and the phase difference detection circuit 13a,
13b, then in step ST4 the generator 1a, 1
The voltage and frequency of b are detected by the voltage / frequency detection circuits 16a and 16b. And voltage difference / frequency difference / phase difference detection circuit
The analog data detected by 13a, 13b and the voltage / frequency detection circuit 16a, 16b is received by the analog input circuit 14a or 14b and converted into a digital signal that can be calculated, and the digital signal line of both units is used by the calculation circuit 7a, 7b. , Exchange the analog input data (step ST5), both power stations 22a, 22b generator
The voltages and frequencies of 1a and 1b are compared (step ST6). If there is a deviation in voltage and frequency, the generators 1a or 1b and the prime movers 2a or 2b are controlled by the parallel operation devices of the two power feed stations 22a and 22b, and are processed so as to be within the specified values (step ST7). And if it falls within the specified value or the voltage
If the frequency deviation is within the specified value, in step ST8, the parallel operation device on the power feed station side with the synchronous closing breaker compares the voltage phases of both power feed stations 22a and 22b until the phases match. Then, when the phase coincidence point is reached, a circuit breaker closing signal is output to the target circuit breakers 3a and 3b and 4a or 4b via the output circuit 8a or 8b. Then, in step ST10, the circuit breaker 3a
Alternatively, parallel operation is started by inserting 3b and 4a or 4b in parallel, and active / reactive power and voltage in the active / reactive power circuits 15a, 15b and voltage / frequency detection circuits 16a, 16b of the generators 1a, 1b. -Detect the frequency (step ST11). Then, in the arithmetic circuits 7a and 7b, the data of both units are compared using the digital communication line between the two power feed stations 22a and 22b, and the active / reactive power is generated while controlling so that the voltage / frequency falls within the specified values. To distribute to the ratio of rated power, the overload side lowers the down signal,
The underload side outputs a raising signal (step ST12) to share the load.

When either one of the parallel operation devices 21a or 21b is abnormal, the process according to the flowchart shown in FIG. 2 (b) is performed. That is, the output from the voltage difference / frequency difference / phase difference detection circuit 13a, 13b, the output from the generator active power detection circuit 15a, 15b, and the busbar communication line active / reactive power detection circuit 17a, 17b Output, output from generator voltage / frequency detection circuit 16a, 16b, and analog input circuit 14a, 1
The self-diagnosis circuit 18a determines whether there is an abnormality from any of the output from 4b, the output from the arithmetic circuits 7a and 7b, the output from the output circuits 8a and 8b, and the data communication signal between the two power feeding stations 22a and 22b. , 18
The judgment is made in b (step ST13). The output circuit 8a of the failure side power supply station 22a or 22b is provided at the location where the failure occurs in either the a power supply station side or the b power supply station side.
8b is reset by the outputs from the self-diagnosis circuits 18a and 18b (step ST14).

Next, set the reference voltage setting circuit 19a or 19b and the reference frequency setting circuit 20a or 20b (step ST15), and
In ST16, the abnormal power feeding station 22a or 22b controls a constant voltage and a constant frequency. In this state, if the other parallel operation device 21b or 21a is normal, the process proceeds from step ST13 to step ST17, where a synchronous closing command of the breakable circuit breaker in the normal side power feed station 22b or 22a is issued. When this synchronous closing command is received, the arithmetic circuit 7a or 7b causes the input switching circuit 12a or 12b to switch the circuit breaker 3a or 3b and 4a or
Switch to 4b (step ST18). Then, step ST19
At the generator circuit breaker 3a or 3b and the busbar circuit breaker 4a
Or voltage difference, frequency difference and phase difference between both ends of 4b
It is detected by the frequency difference / phase difference detection circuit 13a or 13b. In step ST20, both power supply stations are selected due to the voltage difference and frequency difference.
It is determined whether the voltage and frequency of the generators 1a, 1b of 22a, 22b are within the specified values, and if they are not within the specified values, step ST21.
Then, the signal for adjusting the voltage / frequency of only the normal side power supply station 22b or 22a is output, and the process returns to step ST20. Then, when the voltage and frequency of both power feeding stations 22a, 22b are within the specified values, the voltage phases of both power feeding stations are compared only at the normal power feeding station 22b or 22a in step ST22, and after finding the phase matching point. Breaker for generator 3a or 3b and breaker for connecting to busbar
Output the breaker closing signal to 4a or 4b. Then, after the circuit breaker is inserted in parallel in step ST24, that is, if the abnormality is still detected in the self-diagnosis circuits 18a, 18b even after parallel operation, the fault side power supply station 22a or 22b is the same as the circuit 7a at the time of synchronous closing. , 7b remains reset, the reference voltage setting circuit 19a or 19b and the reference frequency setting circuit 20a or 2
0b remains set and is maintained at a constant voltage and a constant frequency. At this time, the normal side power supply station 22b or 22a detects active / reactive power by the active / reactive power detection circuit 17a or 17b for the busbar connecting line (step ST25), and the active / reactive power of the busbar connecting line is detected in step ST26. Judge whether it is zero or not. Then, if the active / reactive power is not zero, in step ST27, a signal for adjusting the voltage / frequency of only the normal side power supply station 22b or 22a is output,
Return to ST26. That is, if the active / reactive power of the busbar connecting line of the normal side power supply station 22b or 22a flows into the normal side power supply station 22b or 22a, the voltage and frequency of the normal side power supply station 22b or 22a is increased to increase the normal side power supply. If it is outflowing from a place, the voltage and frequency are lowered (steps ST26 and ST27) and the parallel operation is continued (step ST28).

In the above embodiment, the digital communication line 100 for exchanging digital signals between the arithmetic circuits 7a and 7b is used as the data communication system between the power feeding stations, but the data communication by the multiplex transmission device is also possible. Good. Further, even when the normal operation is performed up to the synchronous operation and the abnormality is detected during the parallel operation, the control is the same as the control when the normal operation is synchronously applied to the abnormal machine and the parallel operation is performed as described above. That is, on the abnormal machine side where the self-diagnosis device operates, the reference voltage setting circuit and the reference frequency setting circuit hold a constant voltage and a constant frequency, and on the normal side, the active power and reactive power of the busbar connecting line are controlled to zero.

〔The invention's effect〕

According to the present invention, the parallel operation device has a synchronous closing function, a load sharing function, and a self-diagnosis circuit for detecting a failure thereof, and when the self-diagnosis circuit is activated, the failure device can always maintain the reference voltage and frequency. Since it is configured, even if one of the synchronization input device and the load sharing device fails, and even if the electric quantity of the other device in parallel operation becomes unknown when the signal line is short-circuited or disconnected, the normal device can perform synchronization input and load. It is possible to back up the sharing, and even in the case of power generators that are arranged in fractions at each power supply station, the only communication line between power supply stations is a digital communication line. Therefore, if this digital communication line is replaced with a multiplex transmission device, etc. There is an effect that the line can be shortened and the number of lines can be reduced, the operation is easy, and the precision and reliability are high.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a parallel operating apparatus according to an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are for explaining the control operation of the present invention. Is a flow chart showing a normal case, FIG. 3B is a flow chart showing a case where one of the parallel operation devices is abnormal,
FIG. 4 is a circuit diagram showing a conventional synchronization input device, and FIG. 4 is a circuit diagram showing a conventional load sharing device. 1a and 1b are generators, 13a and 13b are voltage difference / frequency difference / phase difference detection circuits, 15a and 15b are generator active / reactive power detection circuits, 16
a, 16b are generator voltage / frequency detection circuits, 17a, 17b are busbar active / reactive power detection circuits, 14a, 14b are analog input circuits, 7a, 7b are arithmetic circuits, 8a, 8b are output circuits, 18a, 18b is a self-diagnosis circuit, and 21a and 21b are parallel operation devices. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] Claim: What is claimed is: 1. In a parallel operation device for controlling a plurality of prime mover driven generators by a plurality of control devices to perform synchronous loading and load sharing, the control device for controlling the generators includes a voltage / frequency of the generators. Detection for detecting analog data of active power / reactive power, voltage difference / frequency difference / phase difference between the generator and the power system side for synchronous input with the power system side, and active / reactive power of the bus connecting line. Circuit, analog input circuit that converts these analog data to digital, voltage, frequency, active power
A digital communication line for receiving reactive power and an abnormal condition of the parallel operation device for other generators, an arithmetic circuit for receiving outputs from the analog input circuit and the digital communication line, and performing arithmetic necessary for synchronous closing and parallel operation, and An output circuit that outputs a signal that drives a circuit breaker that communicates the power generator and the prime mover and the generator with the calculation result of the calculation circuit,
A self-diagnosis circuit that detects abnormalities in the detection circuit, analog input circuit, arithmetic circuit, and output circuit, and a reference voltage / setting that sets the generator to a reference voltage and a reference frequency based on a signal from the self-diagnosis circuit. Each generator is equipped with a circuit and a reference frequency setting circuit, and when the self-diagnosis circuit operates during parallel operation, the reference voltage setting circuit and the reference frequency are set to control the constant voltage and constant frequency, and the self-diagnosis circuit does not operate. A parallel operation device characterized by performing backup load sharing of active power and reactive power at times.