JPH10243547A - Pcm current differential protection relaying scheme - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable protection by a PCM relay even if a device power supply at a specific terminal is interrupted, by locking an adjacent device transmission failure signal with an adjacent device stop end detection signal. SOLUTION: A station 1 to look at receives signals RX1, RX2 from adjacent stations 2, 3. In case power supply is turned off in an adjacent station 2, CB in the adjacent station 2 is turned off, and stop end information is thereby allocated to a transmission frame. If after the circuit breaker at the terminal of the adjacent station 2 is opened, power supply is turned off, a RX1 transmission failure signal a1 is brought in '1'. Since the stop terminal b1 of the adjacent station 2 is at '1' in stop information, however, the stop terminal is locked through an AND circuit 11. In case power supply to a relaying device is turned off, a transmission line kept in use becomes unavailable. However, information on terminal stations other than the terminal station where power supply was turned off can be correctly transmitted by restructuring the transmission line through a loop back process. As a result, if the relaying device at a specific terminal is turned off, it is possible to protect the other terminals through a PCM relay.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PCM current differential protection relay system used for transmission line protection.

[0002]

2. Description of the Related Art In a current differential protection relay system in which a plurality of substations are to be protected, a current differential relay protection device is provided at each substation, and the current taken in at each substation. The information is sent to the other substation via a transmission line such as a metal or fiber optic cable, and the current differential relay protection device installed at the other substation (this also applies to the substation) uses the current information The sum of the current information sent from the other substation is calculated, and the presence or absence of the difference current is detected.

Normally, the current flowing into the protection target section is equal to the current flowing out, so that the difference current is zero. However, if an accident occurs in the protection target section, the difference current is generated. The presence or absence of a difference current can be directly related to the presence or absence of an accident.

[0004] The PCM current differential protection relay device digitally transmits the instantaneous value of the current information by pulse code modulation (PCM) to perform a current differential operation.

FIG. 3 is a block diagram of a two-line power transmission system of 1L and 2L. B terminal and C without power supply,
An example of the D and E terminals is shown.

As shown in FIG. 4, PCM current differential protection relays (hereinafter abbreviated as relays or PCM relays) A to E are installed at each terminal.

FIG. 4 is a conceptual diagram of a system configuration of a general PCM relay system, and shows only a 1-line 1-L protection system. Each of the relay devices A to E is a current transformer C of each terminal in FIG.
The current I from T is sampled, and the instantaneous value of each terminal current obtained by A / D conversion is digitally transmitted to another terminal station (relay device) by pulse code modulation (PCM) and the current information received from the other terminal station is used. It has a sampling circuit, an A / D conversion circuit (not shown), a microcomputer processing unit MDP, a transmission interface INF, an optical-electrical conversion circuit O / E, and an electric-optical conversion circuit E / O for performing a current differential operation. and, the relay device a-E are connected in a loop by an optical fiber OPF ₁ ~OPF _5, and transmits the current data taken by each relay device in the order of Tsugiden device a-E. Also, a sampling signal required for the protection operation, a circuit breaker CB and a line switch LS
Information (sub-commission information) related to operations such as (not shown) is transmitted.

The above is a case where each terminal station is provided with a protection operation function. One or two relays are provided with a protection operation function, and receive a trip command from another main station to receive a trip command. There is also a method of interrupting the circuit breaker CB.

[0009] at all times, as shown in FIG. 5 (a), using optical fibers OPF ₁ ~OPF _4, splicing at OPF ₅ is not used collector A → B → C → D → E → D → C → B Information is exchanged via the route A. As shown in FIG. 5B, for example, when the optical fiber OPF ₃ is disconnected, the relay device D → E → A is used by using the spare route OPF _5.
The route is changed to B->C->B->A->E-> D so that information can be transferred (loopback processing).

[0010]

In the above-mentioned PCM relay system, there is a case where the power supply of the relay is cut off only at a specific terminal in order to inspect or repair the circuit breaker and the relay. In this case, when the power is turned off, the adjacent station detects this as an abnormality and locks 43C (device lock), and the protection operation by the PCM relay becomes impossible. For this reason, when the power of the relay device is turned off, the other terminal stations on the same line are locked in transmission (43C lock), and the terminal in 43C lock requires processing such as relying on post-protection protection. In addition, the circuit breaker of the terminal whose power is to be cut off is generally turned off in advance.

[0011] For example, for inspection of the relay device C of C terminal, in the case of the power source and disconnection, first, open the circuit breaker CB ₃₁ C-terminal. In this state, the other terminal station recognizes that the relay device C is a pause end (rest terminal station), and controls the current of the terminal C to zero, so that an accident occurs at the point F in FIG. Also, the circuit breakers CB ₁₁ , CB ₂₁ , CB ₄₁ , and CB ₅₁ can be properly shut off.

However, if the power of the relay device C is thereafter turned off, the optical signals received from the relay device C are interrupted and the signals cannot be received in the relay devices B and D as shown in FIG. Since it is lost, transmission failure such as reception interruption is detected.
At the time of transmission failure, loopback processing is performed to reconstruct the transmission route. However, at stations that detect transmission failure, that is, at the relay devices B and D, 43C lock (device lock) is performed. Therefore, protection by the PCM relay cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to lock an unnecessary transmission failure signal by combining a transmission failure signal with an idle terminal condition to specify the transmission failure signal. It is an object of the present invention to provide a PCM current differential protection relay system that can be protected by a PCM relay even when the terminal device power is cut off.

[0014]

According to the present invention, a PCM current differential protection relay device is provided at each terminal with a plurality of terminals as a protection target section, and the devices are connected to each other by a loop-shaped transmission line. Each device transmits the current information captured by the substation to the other device, and receives the current information from the other device to detect an accident based on the current information captured by the own device and the current information from the other device. Judge and protect the system, and
In a PCM current differential protection relay system that detects a transmission failure such as reception interruption and reconstructs a transmission route, means for detecting reception interruption of a reception signal from an adjacent device and outputting a transmission failure signal to each device. Means for detecting whether an adjacent device is a pause end using the set adjacent device number and pause end information assigned to each device number on a transmission frame, and transmitting the adjacent device transmission failure signal to the adjacent device. Means for locking with a device idle end detection signal is provided so that when a specific device cuts off the power, an adjacent device is not locked at 43C.

[0015]

FIG. 1A shows a transmission signal TX1 between a relay device (own station) 1 for detecting a transmission failure and adjacent relay devices (adjacent stations) 2 and 3 for turning off the power. And TX2
And the flow of the received signals RX1 and RX2, and FIG. 4B shows a 43C lock sequence circuit.

In FIG. 1, transmission failures (signals) a1, a
2 is each terminal station (own station) 1 (each relay device A to E in FIG. 4)
Are signals detected from the reception interruption of the signals RX1 and RX2 from the adjacent stations 2 and 3, respectively. The adjacent station idle end signal b
1, b2, each terminal station 1 receives the signal RX1 or RX2 from the adjacent station 2 or 3 before the power is turned off, and assigns the set adjacent station No. and the station No. to the transmission frame for each station No. This is a signal that has been determined to be a pause end based on the received pause end information.

Reference numeral 11 denotes an AND circuit for outputting when the RX1 transmission failure signal a1 is "1" on condition that the adjacent station 2 idle end signal b1 is "0".
13 is an AND circuit for outputting when the RX2 transmission failure signal a2 is "1" on condition that the idle station signal b2 of the adjacent station 3 is "0", 14 is an output confirmation timer thereof, and 15 is a timer 1
This is an OR circuit that outputs the outputs 2 and 14 as a 43C lock (device lock) signal.

Next, the operation of the embodiment will be described. The own station 1 receives signals RX from the adjacent stations 2 and 3, respectively.
1 and RX2. When the adjacent station 2 turns off the power,
First, the CB of the adjacent station 2 is turned off, so that the idle end information is allocated to the transmission frame. Then, the circuit breaker of the terminal of the adjacent station 2 is opened, and thereafter, the power of the adjacent station 2 is turned off. As a result, the RX1 transmission failure signal a1 becomes “1”, but the adjacent station 2 and the idle terminal b1 become “1” by the idle information.
, And is locked by the AND circuit 11. Therefore, no 43C lock (device lock) signal is output from the OR circuit 15. Also, no unnecessary transmission failure alarm is issued. Similarly, when the power of the adjacent station 3 is turned off, no 43C lock signal is output.

In other words, when the power of a specific station is cut off, the CB, which cannot be protected in advance, is turned off, so that the station becomes a pause end and passes its information to each terminal. Is detected, the idle end information is received in advance, so that the transmission failure signal is locked and 43
Since the C-lock does not occur, system protection by the reconstructed transmission route becomes possible.

Therefore, as a protection function, if the power of the relay device of the terminal is cut off after the circuit breaker of a certain terminal is opened (pause end), the device of the other terminal does not lock the device, so that the protection is stopped. The edge signal is retained, and system protection can be performed without using information on the idle edge.

When the power supply of the relay device is turned off, the transmission line which is always used cannot be used. However, by reconstructing the transmission line by loopback processing, the terminal other than the terminal station whose power is turned off is turned off. Station information can be transmitted correctly. Therefore, protection by the PCM relay is possible.

Also, in the case of the open loop system in which there is no spare route not used in the normal transmission, the stations at both ends are the same as the case where there is a spare route. For example, FIG.
When the power is cut off after the relay E of the circuit breaker CB is “opened”,
Since the relay device D has a transmission failure from the dormant terminal, the abnormality is locked. Further, since the transmission path is reconstructed so as to be looped back by the relay device D, all information other than the relay device E can be transmitted, so that protection is possible.

[0023]

Since the present invention is configured as described above, the following effects can be obtained.

(1) In a protection system between substations using a PCM relay having a backup route, when the power of a relay device at a specific terminal is cut off, the breaker at the terminal is turned off. By turning off the power, the relay device of the other terminal is not locked by 43C, so that protection by the relay device of the other terminal becomes possible, and no unnecessary alarm is issued.

(2) In a protection system between substations using an open-loop PCM relay having no backup route, the stations at both ends are turned off after the circuit breaker of the corresponding terminal is turned off, as in (1) above. By turning off the power, the other terminals can be protected by the PCM relay, and no unnecessary alarm is issued.

(3) Before turning off the power of the device, a circuit breaker that cannot be tripped due to the turning off of the device is turned off in advance. This system pays attention to this point and “turns off” the circuit breaker.
In this case, it is not necessary to perform an operation such as setting with a switch, so that an erroneous operation and complexity can be prevented.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating an embodiment, in which (a) is an explanatory diagram of a relationship between a local station and an adjacent station, and (b) is a transmission lock sequence circuit diagram in the local station.

FIG. 2 is an open loop configuration diagram.

FIG. 3 is a configuration diagram of a two-line power transmission system.

FIG. 4 is a conceptual diagram of a PCM relay system configuration.

5A and 5B show transmission routes, wherein FIG. 5A is an explanatory diagram of a normal transmission route, and FIG. 5B is an explanatory diagram of a transmission route when a transmission line is disconnected.

6A and 6B show a conventional example, in which FIG. 6A is a 1L side system configuration diagram, and FIG. 6B is a system configuration diagram.

[Explanation of symbols]

1 ... own station (relay device) 2, 3 ... adjacent station (relay device) OPF ... optical fiber A to F ... PCM current differential protection relay device (PCM relay,
RX1, RX2 reception signal TX1, TX2 transmission signal T1, T2 confirmation timer E / O electric / optical conversion circuit O / E optical / electric conversion circuit INF transmission interface MDP Microcomputer processing unit CB: Circuit breaker CT: Current transformer Tr: Transformer

Claims (1)

[Claims] 1. A PCM current differential protection relay device is provided at each terminal with a plurality of terminals as a protection target section, and each device is connected to each other by a loop transmission line. While transmitting the acquired current information to other devices, receiving the current information from the other device, judging an accident from the current information acquired by the own device and the current information from the other device, and performing system protection, In addition, in the PCM current differential protection relay system that reconstructs a transmission route by detecting a transmission failure such as reception interruption, etc., detects a reception interruption of a reception signal from an adjacent device and outputs a transmission failure signal to each device. Means for detecting whether an adjacent device is a dormant end by using the set adjacent device number and dormant end information assigned to each device number on a transmission frame, and The neighboring device idle end detection PCM current differential protection characterized in that, when a specific device turns off the power, a circuit breaker is cut off in advance to make it a rest end so that an adjacent device does not lock the device. Relay method.