JP3353573B2 - Method for determining synchronization establishment in current differential relay - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for determining synchronization establishment in a current differential relay device using an optical transmission line or the like.

[0002]

2. Description of the Related Art When a power system is protected by a current differential relay system, the synchronization of current data becomes important.
In actual protection, remote devices are connected by an optical fiber cable or the like, a reference synchronization signal is separated from a transmission line, and each device takes in current data based on the synchronization signal.

When a plurality of devices are connected, the connection method includes a star connection, a loop connection, and an open loop connection, but a loop connection or an open loop connection is often used from the viewpoint of economy. 4A shows an example of loop connection, and FIG. 4B shows an example of open-loop connection, in which three-terminal devices A, B, and C are connected by an optical fiber cable lo.

[0004]

In a loop system in which a reference synchronization signal passes through each device, if a failure occurs at any one point of a cable or a device, the flow is interrupted.
For this reason, a loopback process or the like is normally performed to reconstruct the transmission path. For example, device A as shown in FIG. 5, if the break in F ₁ point between B occurs, device A is the master station (M
S) from the return station (TS '), the device B from the remote station (RS) to the master station (MS'), and the device C from the return station (TS) to the remote station (RS '). If it is restored, it will return to the original station.

[0005] However, this processing can be re-established at a single disconnection, but cannot be re-established when disconnections or device failures occur at a plurality of locations.

Further, in the open loop system, if a disconnection occurs even at one location, there is no detour route, so that reconstruction is not possible.

As a countermeasure against a disconnection or a device failure at a plurality of points in the loop system or an open loop system, a complete duplexing or the like can be considered. Here, a countermeasure under a specific situation will be considered.

[0008] In a multi-terminal system, a so-called idle end state, in which a circuit breaker is opened for periodic inspection or the like to disconnect a part from the system, is considered. An example is shown in FIG. The illustrated example is a multi-terminal system in which a power source G is connected to one terminal, a load L is connected to the other four terminals, and a breaker CB is disposed between each terminal and the power line PL. The terminal in the state (shown with a cross over the circuit breaker) is the idle end.

At this time, the equipment installed at the target substation is often put into a halt state. However, since the system wants to utilize the protection function as much as possible in the remaining devices other than the idle end, the data at the idle end should be ignored. An example is shown in FIG. In the illustrated example, the relay devices A, B, C, D, and E are installed at the five terminals of the system in FIG. 6 and connected by the optical fiber cable lo (open loop system).
Therefore, the data of the device E at the idle end is ignored by the devices A to D of the other terminals. In addition, CT is a current transformer.

As shown in FIG. 8, the flow of the synchronization signal is transmitted from the master station MS (apparatus A) on the downstream route in both the loop system and the open loop system, and is returned to the upstream route by the return station TS (device C). Take the form In this case, the synchronization signal arrives at the predetermined return station and returns to the master station, so that "all-station synchronization" is achieved.Since the system can be used, if information is interrupted halfway, "all-station synchronization" does not occur. As a result, the system is locked.

[0011] The present invention has been made in view of the above circumstances, and when a state of disconnection from the system occurs,
An object of the present invention is to provide a method for determining synchronization establishment in a current differential relay device that can maintain a system as usable as possible by determining a state equivalent to “all-station synchronization”.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a multi-terminal current differential relay device, in which the open loop transmission path is disconnected or the power of the device is disconnected. Either terminal is at rest and the device at that terminal is disconnected from the system, or multi-terminal
Rest on loop transmission line of current differential relay system
There may be two disconnections across the device or the power
The same state as the open loop method
Sub-communication at the master station
The "ready signal" bit in the information indicates that other devices are correct.
Understand the normal state and take a break with sub-communication information
Detects a device at the stop end, and if it is a pause end,
By forcing the device to “ready signal present”,
Know the number of "ready signal" inputs and check if the number of devices in the system
The number of “ready signal” inputs matches the number excluding the own station.
Time, the condition that the device that is not synchronized
It is characterized in that it is determined that “synchronization is established at the station ” and the same treatment as the all-station synchronization is performed.

[0013]

[0014]

[0015]

FIG. 1 shows an embodiment of the present invention. FIG. 1A is a transmission line configuration diagram showing an example of a failure situation in the open loop system, and FIG. 1B is a circuit diagram showing a synchronization sequence in the open loop system.

An example of a failure situation is a configuration in which relay devices A (master station MS), B (remote station RS), and C (return station TS) are installed at three terminals, and the transmission line between the devices B and C is disconnected. Occurs, and the installation terminal of the device C becomes a rest end. In this case, the device B changes from the remote station RS to the return station TS 'and enters a temporary station state, and the devices A and B ignore the data of the device C.

The synchronization sequence includes an all-stations synchronization determination signal 1,
It is formed using the MS idle end detection signal 2, the TS idle end detection signal 3, the open loop setting signal 4, and the synchronization establishment determination signal 5 in the remaining devices. That is, the MS idle end detection signal 2
And an OR of the TS pause end detection signal 3 (OR circuit OR1), and an AND of the OR output and the open loop setting signal 4 (AND circuit AND1).
The AND output is ANDed with the synchronization establishment determination signal 5 in the remaining device (AND circuit AND2). Next, the AND output is ORed with the all-stations synchronization determination signal 1 (OR circuit OR).
2) The OR output is used as a synchronization establishment signal.

FIG. 2 shows another embodiment of the present invention. FIG.
FIG. 2A is a transmission line configuration diagram showing an example of a failure situation in a loop system, and FIG. 2B is a circuit diagram showing a synchronization sequence in a loop system.

An example of a failure situation is a configuration in which relay devices A (master station MS), B (remote station RS), and C (return station TS) are installed at three terminals, and transmission lines on both sides of the device B at the idle end. Is a case where a disconnection occurs. In this case, the situation becomes the same as that of the open loop system, and the apparatuses A and C are connected to the apparatus B.
Ignore data. In the loop method, conditions such as devices at both ends are unnecessary, and if synchronization is established between the remaining devices,
Treat the same as all station synchronization.

The synchronization sequence includes an all-stations synchronization determination signal 1,
Loop setting signal 6 and synchronization establishment determination signal 5 in remaining devices
It is formed by using. That is, the AND of the loop setting signal 6 and the synchronization establishment determination signal 5 in the remaining device is obtained (AND circuit AND3), and the AND output and the all-station synchronization determination signal 1 are ORed (OR circuit OR3), and the OR output is synchronized. Establish signal.

Regarding the determination of synchronization establishment in the remaining devices,
This will be described with reference to FIG. FIG. 3A is a transmission path configuration diagram,
FIG. 3B is a sequence circuit diagram.

As described above, the transmission path is of the open loop type, and the relay devices A, B, C, and D are arranged in the order. The device A at one end is a master station.

The determination of the establishment of synchronization by the remaining devices is based on the fact that each station grasps the normal state of the other devices by the "ready signal" bit in the sub-communication information.
Utilizing the fact that it is possible to detect whether or not the device installation end is a pause end based on the sub-communication information. Also, since the number of devices in the system is stored by settling, it is possible to judge that the system can be used by receiving ready signals only for the number excluding the own station. The fact that the information of the device can be neglected by setting "ready signal present" is utilized.

The sequence for establishing the remaining device synchronization in the device (master station) A is formed based on the above-mentioned reasons. That is, the signal 11B of “the station B ready signal exists” and the signal “B
OR of signal 12B of "station pause end", signal 11C of "C station ready signal" and OR of signal 12C of "station C pause end", signal 11D of "station D ready signal" and "D station pause end" Of each signal 12D (OR circuit 1
3, 14, 15), and each OR output is applied to the matching circuit 16. The matching circuit 16 receives the number of devices N from the device number input unit 17.
Is determined, and it is determined whether or not (N-1) and the input number of the ready signal (including the number at the idle end) match. The coincidence output is input to the inhibit circuit 18. An output signal of a determination unit 19 for determining the presence or absence of an asynchronous device is applied to a prohibition input terminal of the inhibit circuit 18.
Is a signal of "synchronization established with remaining devices".

The determination unit 19 determines that there are no more unsynchronized devices because there are no more unsynchronized bits. In the device at the idle end, the asynchronous bits disappear with the disconnection, so that there is no problem in establishing the synchronization.

When it is determined that synchronization has been established in the remaining devices in this manner, even if a failure occurs in the open loop system (FIG. 1),
Even in the case of a failure in the loop system (FIG. 2), the establishment of synchronization in the remaining devices excluding the idle end is determined immediately, and the protection system is effectively used.

In the loop system, the same situation occurs even when the power supply of the paused end device is cut off in addition to the disconnection of the transmission line at two places across the device at the paused end. In addition, when one point is broken in the loop method, the route is reconstructed by the loop back process.

[0028]

As described above, according to the present invention, in the open loop system, when both ends or any of the terminals are at the idle end, the idle end device is disconnected from the system due to a transmission line failure or the like. In the case of the loop system, if the same situation as the open loop system occurs, such as when a transmission line failure occurs across the idle end device, the establishment of synchronization between the remaining devices is determined and treated as the same as all-station synchronization. Therefore, the protection operation can be continued and the protection system can be effectively used.

[Brief description of the drawings]

FIG. 1 shows an embodiment (open loop system) of the present invention, in which (a) is a transmission line configuration diagram of an example of a failure situation,
(B) is a synchronous sequence circuit diagram.

FIGS. 2A and 2B show another embodiment (loop system) of the present invention, in which FIG. 2A is a diagram of a transmission line configuration in a failure situation example, and FIG. 2B is a diagram of a synchronous sequence circuit.

3A and 3B are diagrams for explaining an example of determining synchronization establishment between remaining devices in each embodiment, wherein FIG. 3A is a diagram of a transmission line configuration, and FIG. 3B is a diagram of a synchronization sequence circuit.

4A and 4B are diagrams for explaining a connection method of a current differential relay device of each terminal of a multi-terminal system, in which FIG. 4A is a diagram of a transmission line configuration of a loop system, and FIG. Diagram.

FIG. 5 is a transmission line configuration diagram for explaining a loopback process in a loop method.

FIG. 6 is a system configuration diagram for explaining a multi-terminal system having a pause end.

FIG. 7 is a configuration explanatory view showing an example of a multi-terminal protection system configuration (open loop system).

FIG. 8 is an explanatory diagram showing a data flow in a transmission path.

[Explanation of symbols]

A to E: Relay device lo: Optical fiber cable OR1 to OR3: OR circuit AND1 to AND3: AND circuit 1: All-station synchronization determination signal 2: MS idle end detection signal 3: TS idle end detection signal 4: Open loop setting signal 5 ... Synchronization establishment signal in the remaining device 6 ... Loop setting signal 11B (C, D) "B (C, D) station ready signal exists"
12B (C, D) signal of "B (C, D) station idle end" 13 to 15 ... OR circuit 16 ... Matching circuit 17 ... Number of devices input unit 18 ... Inhibit circuit 19 ... Judgment unit

Claims (2)

(57) [Claims] 1. An open-loop transmission line of a multi-terminal current differential relay device having a break in an open-loop transmission line or a power cut-off of the device. If the device at that terminal is disconnected from the system, the master station displays
The normal status of other devices by the
Has been suspended due to sub-communication information
The device is detected, and if it is at rest, the device is
The "ready signal"
Know the number of inputs, the number excluding the own station from the number of devices in the system
When the number of ready signal inputs matches the
"Synchronization established with the remaining devices" on condition that the device has been canceled
And determining that synchronization is established in the current differential relay device. 2. An open loop, for example, in which a disconnection occurs at two points in a loop transmission path of a multi-terminal system current differential relay device with a pause end device sandwiched therebetween, or a power interruption of the pause end device occurs. If the same situation as in the system occurs, the master station reads “Ready” in the sub-communication information.
The normal status of other devices by the
Has been suspended due to sub-communication information
The device is detected, and if it is at rest, the device is
The "ready signal"
Know the number of inputs, the number excluding the own station from the number of devices in the system
When the number of ready signal inputs matches the
"Synchronization established with the remaining devices" on condition that the device has been canceled
And determining that synchronization is established in the current differential relay device.