JP3228582B2 - Step-out separation relay - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-out separation relay for detecting a step-out when a step-out occurs in a power system, performing system separation between the step-out systems, and preventing an accident from spreading to all systems. Related to the device.

[0002]

2. Description of the Related Art In the event of a major power system accident, the power system loses synchronism, and if left unattended, the synchronization of a large number of generators is lost, eventually causing a major power failure. As a countermeasure, step-out separation relays are installed at various points in the system. Hereinafter, a conventional apparatus will be described with reference to the drawings. FIG. 5 is a diagram illustrating the configuration of a power system to which a step-out separation relay device is applied and a conventional step-out separation relay device. In FIG. 5, 21A and 21B are power systems, 22A to 22E are transmission lines interconnecting the 21A and 21B power systems, 23A to 23D are buses of electric stations between the 21A and 21B power systems, and 24A is a transmission line. Circuit breaker installed at 22A, 24
B and 24C are circuit breakers installed on transmission line 22B, 24D and 24E
Is the circuit breaker installed on transmission line 22C, 24F and 24G are transmission lines
A circuit breaker installed on 22D, 24H is a circuit breaker installed on transmission line 22E, 25A is an instrument transformer installed on bus bar 23A,
Similarly, 25B to 25D are instrument transformers installed in buses 23B to 23D, respectively, and 26A is the bus voltage from instrument transformer 25A.
Step-out separation relay that detects step-out from the 23B bus voltage and separates the system when step-out is detected. 26B is an instrument transformer.
A step-out separation relay that detects out-of-step from the bus voltage from 25B and the bus voltage of 23A and separates the system when step-out is detected.Similarly, 26C to 26F Out-of-step detection relay, and out-of-step separation relay that separates the system when out-of-step is detected.27A transmits and receives the bus voltage information of the own substation and the other substation between the 26A and 26B out-of-step separation relays. Similarly, 27B and 27C are transmission systems for transferring bus voltage information between the own electric station and the out-of-step separation relay device of the partner electric station.

In such a configuration, the operation of the step-out separation relay devices 26A and 26B installed on the transmission line 22B will be described. The step-out separation relay 26A is connected to the bus from the instrument transformer 25A.
Introduce the system voltage of 23A to its own device, and
Out-of-step separation relay device 26B installed at the partner substation using
To the system voltage of the bus 23A. Similarly, the out-of-step separation relay device 26B introduces the system voltage of the bus 23B from the instrument transformer 25B to its own device, and transmits it to the out-of-step separation relay device 26A installed at the partner electric station using the transmission system 27A. The system voltage of the bus 23B is transmitted. Each of the out-of-step separation relay devices 26A and 26B calculates the phase angle difference of the bus voltage of the own electric station and the other electric station, and when the phase angle difference is more than 180 degrees, the electric center of the out-of-step between both electric stations. It is determined that there is a point, and step-out is detected. FIG. 6 shows an example of the characteristic. FIG. 6A shows the case where the phase angle difference between the own electric station voltage VA and the other electric station voltage VB is within 180 degrees, and the out-of-step detection relay does not operate. (b) is the own electric station voltage VA
This is a case where the phase angle difference between the counterpart electric station voltage VB is 180 degrees or more and the step-out detection relay operates. Then, when a step-out is detected, the circuit breaker 24B is switched by the step-out separation relay device 26A,
Disconnect circuit breaker 24C with step-out separation relay device 26B, and
And system 2 to prevent the loss of synchronization.
Similarly, the out-of-step separation relays of 26C and 26D installed on the transmission line of 22C detect out-of-step from the phase angle difference between the bus voltage of 23B and the bus voltage of 23C, and the breakers of 24D and 24E are respectively installed. After tripping, the system 1 and the system 2 are separated. In addition, the step-out separation relays 16E and 26F installed on the transmission line 22D detect step-out based on the phase angle difference between the bus voltage 23C and the bus voltage 23D, and disconnect the circuit breakers 24F and 24G. The system 2 is separated.

[0004]

According to the above prior art, the system is separated at the electrical center point of the out-of-step between the system 1 and the system 2. In the case where active power is being sent to the system 2, if the system is separated by the transmission line 22B, the step-out phenomenon between the system 1 and the system 2 disappears, but the system 1 transmits power to the system 2 until the step-out occurs. The amount of active power that was
System frequency rises. On the other hand, in the system 2, the active power received from the system 1 before the occurrence of step-out becomes insufficient, and as a result, the system frequency of the system 2 decreases. As a countermeasure against the system frequency rise and fall of the system after the system separation by the step-out separation, the generator is cut off in the frequency increase system and the load is cut off in the frequency decrease system, and the operation of each separation system is maintained. ing. Normally, in order to return the frequency of the separation system to a steady value, the amount of generator shutoff and the amount of load interruption performed in each separation system need to be equal to the amount of active power in advance at the system separation point. Therefore, as the pre-active power amount at the system separation point is larger, the generator cutoff amount and the load cutoff amount in each separation system are larger, and the influence on the entire system is also larger.

On the other hand, in the case of the system shown in FIG. 5, a load (not shown) is connected to the bus of each electric station. In this case, the active power sent from the system 1 is divided into a load connected to the bus 23A, a load connected to the bus 23B, a load connected to the bus 23C, and a load connected to the bus 23D. It is consumed and the balance is supplied to the system 2. That is, the amount of active power flowing through the transmission line is
There is a relationship of active power flowing through B> active power flowing through transmission line 22C> active power flowing through transmission line 22D. The machine cutoff amount and the load cutoff amount also differ. However, since the conventional step-out separation relay performs system separation at the electrical center point of step-out, the system is separated by one of the transmission lines 22B, 22C, and 22D regardless of the active power beforehand at the separation point. You. The present invention has been made in view of the above circumstances, it is possible to determine the system separation point according to the active power amount of the interconnecting transmission line before step-out, it is possible to minimize the effect on the separation system An object is to provide a step-out separation relay device.

[0006]

According to the present invention, when a step-out occurs in the power system, the step-out is detected and the system separation is performed between the step-out systems to prevent the spread of the accident to all the systems. In the power transmission device, means for detecting out-of-step between the target systems, means for measuring the active power of each transmission line interconnecting a plurality of electric stations having loads between the target systems, and The transmission line has a means for selecting a transmission line having a minimum prior value before a step-out occurs among active power values, and a means for cutting off the selected transmission line and detecting a system disconnection upon detection of step-out.

According to the above-mentioned means, when out-of-step between the target systems is detected, system separation is performed on the transmission line having the smallest active power value before out-of-step occurs in each transmission line. It is possible to provide a step-out separation relay device capable of minimizing an increase and a decrease in system frequency and minimizing the influence on each separation system.

[0007]

An embodiment will be described below with reference to the drawings. FIG.
FIG. 1 is a diagram for explaining a configuration of a power system to which a step-out separation relay device according to the present invention is applied and a step-out separation relay device. In FIG. 1, 11A and 11B are power systems, 12A to 12E are transmission lines interconnecting the power systems 11A and 11B, and 13A to 13D are power systems.
The busbar of the electric station between 11A and 11B, 14A is the circuit breaker installed on the transmission line 12A, 14B and 14C are the circuit breakers installed on the transmission line 12B, and 14D and 14E are the circuit breakers installed on the transmission line 12C. , 14F and 14G are circuit breakers installed on transmission line 12D, 14H
Is a circuit breaker installed on the 12E transmission line, 15A is an instrument transformer installed on the bus 13A, and similarly, 15B to 15D are buses respectively.
Instrument transformers installed in 13B to 13D, 15E are instrument current transformers installed in the 12B transmission line, and similarly, 15F and 15G are instrument current transformers installed in the transmission lines 12C and 12D, respectively. 16A is the load connected to the substation bus 13A, similarly 16B to 16D
Is a load connected to buses 13B to 13D of the substation, 17A
, 17B respectively introduce the bus voltage from the instrument transformers 15A, 15D, and the terminal devices 1, 17C, 17D, 17E for transmitting the bus voltage information to the 18 arithmetic units, respectively, are the instrument transformers 15A, 15B.
, 15C and the transmission line current from the 15E, 15F, and 15G current transformers, and measure the active power flowing through the 12B, 12C, and 12D transmission lines. And based on a command from the arithmetic unit 18,
Terminal devices 2 and 18 that open circuit breakers 14B, 14D and 14F
Step-out detection is performed based on the bus voltage from the terminal device 1 of 17A and the bus voltage from the terminal device 1 of 17B.
The minimum active power transmission line before out-of-step occurs is selected from the active power values of the interconnected transmission lines from the terminal devices 2 of D and 17E, and a system separation command is issued to the terminal device 2 that cuts off the selected transmission line when out-of-step is detected. 19A and 19B are transmission systems for transferring bus voltage information from the terminal devices 1 of 17A and 17B to the arithmetic devices of 18 respectively, and 19C, 19D and 19E are 17C, 17D and 19E respectively.
This is a transmission system that exchanges the active power value of the interconnection transmission line and the system status system separation command information between the terminal device 2 of 17E and the arithmetic unit of 18.

In such a configuration, the operation of the out-of-step separation relay device of the present invention will be described. 17A terminal device 1
Detects the system voltage of bus 13A from instrument transformer 15A,
The bus voltage information is transmitted to the arithmetic unit 18 using the transmission system 19A. Similarly, terminal device 17B is connected from instrument transformer 15D to bus 13
The system voltage of D is detected, and the arithmetic unit 18 is
To the bus voltage information. The arithmetic unit 18 calculates the phase angle difference between the bus voltages of the two electric stations, and when the phase angle difference is 180 degrees or more, determines that there is an electrical center point of the step-out between the two electric stations, and detects the step-out. Perform The characteristics of the step-out detection relay are the same as those in FIG.

On the other hand, the terminal device 17C constantly measures the active power value of the transmission line 12B and transmits the active power value information to the arithmetic unit 18 using the transmission system 19C. Similarly, the terminal devices 17D and 17E constantly measure the active power values of the transmission lines 12C and 12D, respectively, and transmit the active power information to the arithmetic unit 18 using the transmission systems 19D and 19E. The arithmetic unit 18 always selects and stores the transmission line having the smallest absolute value of the active power of the transmission lines 12B, 12C, and 12D transmitted from the terminal device 2 before the step-out detection, and detects the step-out. Sometimes keep the selection result. At this time, even if the out-of-step detection is sent, the selection result is stored before a certain time so that the minimum value can be selected with the active power in advance. At the time of step-out detection, a system separation command is transmitted to the terminal device 2 of the transmission line having the minimum pre-active power according to the held pre-active power minimum selection result. In the terminal device 2 that has received the system separation instruction, the terminal device 17C and the circuit breaker 14B in the terminal device 17C, respectively.
In the terminal device 17D, the circuit breaker 14D is opened, and in the terminal device 17E, the circuit breaker 14F is opened to separate the systems 1 and 2.

FIGS. 2 to 4 show examples of system separation points when step-out is detected.
Shown in FIG. 2 shows a case where power is transmitted from the grid 1 to the grid 2 in the prior state. Since the active power is sequentially consumed by the loads 16B and 16C, the absolute value P1 of the active power flowing through the transmission line 12B> There is a relationship of the active power P2 flowing through the electric line 12C> the absolute value P3 of the active power flowing through the transmission line 12D. In this case, the transmission line with the minimum active power value beforehand is 12D, and the circuit breaker 14F via the terminal device 17E is opened to separate the system. FIG. 3 shows a case where the grid 1 is receiving power from the grid 2 in the prior state.
Since active power is sequentially consumed by the loads 16C and 16B, the absolute value P1 of the active power flowing through the transmission line 12B <the absolute value P2 of the active power flowing through the transmission line 12C <the absolute value P3 of the active power flowing through the transmission line 12D In a relationship. In this case, the transmission line with the minimum pre-active power value is 12B, and the circuit breaker 14B
And separate the system. Fig. 4 shows the load 16
This is a case where the capacity of C is large and equal amounts of power are supplied from the system 1 and the system 2 in the opposite direction. Since the power of transmission line 12B consumes active power at load 16B, transmission line 12B
Value of active power flowing through transmission line 12C = Absolute value of active power flowing through transmission line 12C> Absolute value of active power flowing through transmission line 12C
P2. In this case, the transmission line with the smallest active power value beforehand is 12C, and the circuit breaker 14D via the terminal device 17D is opened to separate the system. In the above embodiment, the terminal device 2 is 3
Although described individually, it can be arbitrarily installed according to the number of electrical stations between the system 1 and the system 2. Further, the functions of the arithmetic device can be built in any of the representative terminal devices. Further, the step-out detection method is not limited to the configuration of FIG. 1 and the relay characteristics of FIG.

[0011]

As described above, according to the present invention, when out-of-step between target systems is detected, system separation is performed on a transmission line having the minimum active power value of an interconnecting transmission line before out-of-step occurs. As a result, the frequency rise and fall of the separation system were minimized,
A highly reliable step-out separation relay device that can minimize the influence on each separation system after system separation can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a step-out separation relay device according to the present invention.

FIG. 2 is a diagram for explaining an example of a system separation point when step-out is detected according to the present invention.

FIG. 3 is a diagram for explaining an example of a system separation point when step-out is detected according to the present invention.

FIG. 4 is a diagram for explaining an example of a system separation point when step-out is detected according to the present invention.

FIG. 5 is a diagram illustrating a configuration of a conventional step-out separation relay device.

FIG. 6 is a diagram for explaining characteristics of a step-out detection relay.

[Explanation of symbols]

 11A, 11B, 21A, 21B Power system 12A to 12E, 22A to 22E Transmission line 13A to 13D, 23A to 23D Electric station bus 14A to 14H, 24A to 24H Circuit breaker 15A to 15D, 25A to 25D Instrument transformer 16A 1616D Load 17A, 17B Terminal 1 17C 17E Terminal 2 18 Arithmetic unit 19A 1919E, 27A 2727C Transmission system 26A 2626F Step-out separation relay

Claims (1)

(57) [Claims] An out-of-step separation relay device for detecting out-of-step and performing system separation between out-of-step systems when an out-of-step occurs in a power system to prevent an accident from spreading to all systems. Means for detecting out-of-synchronization, means for measuring the active power of each transmission line interconnecting a plurality of electric stations having loads between the target systems, and step-out in the measured active power value of each transmission line. A step-out separation relay device comprising: means for selecting a transmission line having a minimum prior value before the occurrence of a step-out, and means for disconnecting the selected transmission line and performing system separation when step-out is detected. .