JP2013141319A - Protection relay system and transit time fixing method of protection relay system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protection relay system capable of fixing a transmission delay time to a synchronous frame at all times and performing highly-accurate sampling synchronization control.SOLUTION: A frame 101 from a client 3(1) is transmitted to a transit time fixing device 2 through a port PHY22(1). Frame type determination means 25a in a control circuit 25 determines a frame type of the frame 101 transmitted from the client 3(1). Destination determination means 25b identifies a frame control circuit 23(n+1) subjected to a delay command by acquiring a destination address from the received frame 101. The frame 101 determined as the synchronous frame is delayed by prescribed time delay means 26a for a prescribed time in the identified frame control circuit 23(n+1).

Description

  The present invention relates to data transmission / reception and sampling synchronization control in a current differential protection relay, and relates to a technique capable of fixing a transmission delay time for a synchronization frame.

  In recent years, it is common for current differential protection relay devices to perform data transmission / reception and sampling synchronous control using relay-dedicated communication equipment with little fluctuation in transmission delay time. It is desired to develop a protection relay device capable of realizing high-precision sampling synchronous control using a network such as a trademark (hereinafter the same).

  In a conventional protection relay device, the following configuration of a digital current differential relay is employed in order to realize highly accurate sampling synchronous control (see Non-Patent Document 1). This digital current differential relay, as shown in FIG. 8, between the sampling terminal time of its own station and the reception time of the timing flag (TF) which is the sampling timing data from the other terminal between the two terminals having the master station and the slave station. The time intervals are measured (TM and TS), respectively, and the sampling synchronization error (ΔT) is calculated from the time intervals TM and TS.

  That is, in this relay, the master station and the slave station transmit the time interval TM or TS to the counterpart device, and correct the sampling timing based on the sampling synchronization error ΔT. The transmission format in this relay has a fixed frame length and is transmitted with a fixed time difference with respect to the sampling reference signal.

  In this sampling synchronization control, as shown in FIG. 8, the upstream and downstream transmission delay times between opposite terminals are equal, that is, the upstream transmission delay time Tdu of the timing flag TF from the slave station to the master station, The transmission delay time Tdd downstream of the timing flag TF from the station to the slave station needs to be equal.

  In order to realize highly accurate time synchronization, a sampling control method that applies the following restrictions has also been proposed (see Patent Document 1). In this method, the length of the frame to be transmitted is fixed, the length is limited to a certain value or less, and a switching hub equipped with a priority transmission function that preferentially relays synchronous frames is adopted. doing.

Published by the Institute of Electrical Engineers of Japan "Protective Relay System Engineering"

JP 2000-332809 A

  By the way, in the sampling synchronization control in which the master station and the slave station transmit the time interval TM or TS to the partner apparatus and correct the sampling timing based on the sampling synchronization error ΔT, the transmission delay time Tdu upstream of the timing flag TF is transmitted. And the downstream transmission delay time Tdd must be equal.

  However, when a network such as Ethernet is used, it is difficult to make the upstream transmission delay time Tdu equal to the downstream transmission delay time Tdd. The reason is that a plurality of relay apparatuses are generally arranged in the network, and a delay occurs when a frame passes through the relay apparatuses.

  The delay time varies depending on the load state of the network, and further, the delay time changes depending on the order of frame processing in the network relay apparatus. For this reason, the transmission delay time for the frame to pass through the relay device in the network cannot be made constant, and the round-trip transmission delay time between the master station and the slave station is not equal, so high-precision sampling synchronization control cannot be realized. It was.

  Here, the point that the transmission delay times do not match in the relay apparatus (Ethernet switch) when the network is used will be described in more detail with reference to FIG. FIG. 9 shows a configuration in which the clients 3 (1) to 3 (n) and the server 4 are connected to the Ethernet switch 1.

In the configuration as shown in FIG. 9, the frame transmission delay times of the clients 3 (1) and 3 (2) via the Ethernet switch 1 are obtained as follows.
First, the client 3 (1) transmits the frame 101 having the destination as the server 4 on the cable 31 (1-1), and immediately after that, the client 3 (2) has the destination on the cable 31 (2-1). Is transmitted with the server 4 as the server 4. The time chart 1 showing the transmission timing of the frame on the cable at this time is as shown in FIG.

The frames 101 and 102 arrive at the Ethernet switch 1 with a time difference Tdef shown in the time chart 1, and the frame 101 is delayed from the Ethernet switch 1 by T101 and output onto the cable 31 (2-n + 1). On the other hand, since the frame 102 is being output, the frame 102 waits until the output of the frame 101 is completed. As shown in FIG. 10, after the waiting time T102, the cable 31 (2-n + 1)
) Is output above.

  That is, as shown in the time chart 1 of FIG. 10, the time T101 when the frame 101 passes through the Ethernet switch 1 and the time T102 when the frame 102 passes through the Ethernet switch 1 are not the same. For this reason, it is difficult to make the frame transmission delay time constant, and the uplink and downlink transmission delay times between the two terminals do not match when a network is used.

  Here, T102, which is the transit time of the frame 102 through the Ethernet switch 1, is determined by the transmission speed and the frame length of the frame 101. Therefore, if the transmission rate is 100 Mbps and the frame length of the frame 101 is 12320 bits, which is the maximum length of the standard, T102 is approximately 123 μs. On the other hand, T101, which is the transit time of the frame 101 through the Ethernet switch 1, is determined by the delay time of the hardware in the Ethernet switch 1, and is usually about several hundred ns.

  Thus, since the delay time for the frame to pass through the Ethernet switch 1 varies from several hundred ns of T101 to 123 μs of T102, it is difficult to fix this delay time.

  Further, in a method using a switching hub with a priority transmission function that fixes a frame length and limits it to a certain length or less, and further relays a synchronization frame preferentially as described in Patent Document 1. Although the fluctuation of the transmission delay time is reduced, the frame length is limited to a certain value or less, so the extensibility of the frame is sacrificed. Furthermore, even if the frame length is set to a certain value or less, the transmission delay time fluctuates for this frame length.

  The present invention has been proposed in order to solve the above-described problems, and its purpose is to protect the synchronization delay control so that the transmission delay time can always be fixed with respect to the synchronization frame and high-precision sampling synchronization control is possible. It is to provide a transit time fixing method for a relay system and a protective relay system.

(1) In order to achieve the above-described object, the present invention includes a plurality of protection relay devices, and the protection relay device protects the power system based on the electrical quantity information of the power system. A protection relay system that performs sampling synchronization between the protection relay devices via a network, and a frame type determination unit that determines whether a frame received from the protection relay device via the network is a synchronization frame; And a fixed time delay means for delaying transmission of the frame to the counterpart protection relay device for a fixed time when the frame type determining means determines that the frame is a synchronous frame.

Moreover, it is one aspect | mode of this invention to provide following (2)-(9).
(2) The fixed time delay means transmits a frame by FIFO.
(3) The frame type determination means determines a synchronization frame based on a frame type added to the frame by the protection relay device.

(4) The fixed time delay means delays a fixed time longer than a time obtained by dividing the length of the frame by a transmission rate.
(5) The fixed time delay means passes the frame without delaying for a fixed time when the frame type determination means determines that the frame is not a synchronous frame.
(6) The fixed time delay means is provided for each protection relay device.

(7) The frame includes destination address information for specifying the target fixed time delay means, and includes destination specifying means for specifying the fixed time delay means for each frame based on the destination address information. about.
(8) When the delay frame determining means for determining whether or not the synchronization frame being delayed exists by the fixed time delay means, and when the delay frame determining means determines that the delayed synchronization frame exists, Delay means for delaying a frame determined not to be a synchronous frame by the frame type determination means.
(9) The delay means delays until the delay of the synchronization frame is completed.

  Moreover, what looked at the said (1)-(9) this invention from the viewpoint of the passage time fixing method of a protection relay system is also one aspect | mode of this invention.

  According to the present invention as described above, it is possible to realize highly accurate sampling synchronization control because the Ethernet switch does not cause a difference in the round trip transmission delay time of the synchronization frame. Conventionally, it has been necessary to limit the frame length to a certain value or less in order to minimize the delay time variation in the Ethernet switch. However, by applying the present invention, the frame length is not limited and a large amount of information is required. Can be transmitted efficiently.

1 is a block diagram showing an example of the overall configuration according to the first embodiment of the present invention. The block diagram which shows the specific structural example of the determination circuit in the passage time fixing device which concerns on the 1st Embodiment of this invention. The figure which shows the time chart 2 of the flame | frame which concerns on the 1st Embodiment of this invention The block diagram which shows the specific structural example of the frame control circuit which concerns on this invention The figure which shows the time chart 3 of the flame | frame which concerns on the 2nd Embodiment of this invention. The figure which shows the time chart 4 of the flame | frame which concerns on the 3rd Embodiment of this invention. The block diagram which shows the example of whole structure which concerns on other embodiment of this invention. The figure which shows the sampling synchronization of the digital current differential relay which is prior art Block diagram showing the overall configuration of the prior art The figure which shows the time chart 1 of the frame which concerns on a prior art Diagram showing an example of frame configuration

[This embodiment]
[1.1. overall structure]
Next, a configuration according to the present embodiment will be described below with reference to FIG.
As shown in FIG. 1, as an overall configuration of the present embodiment, an Ethernet switch 1, a client 3 (1) to a client 3 (n), and a server 4 are connected via a transit time fixing device 2 that is a part of the present invention. It is. Here, as the clients 3 (1) to 3 (n) and the server 4, general devices such as a current differential protection relay device having network interface hardware are adopted.

  The Ethernet switch 1 is a general-purpose switching hub that is a relay device in the network, and analyzes data sent from the clients 3 (1) to 3 (n) and the server 4 via the transit time fixing device 2. Thus, the destination is detected and transmitted to the destination clients 3 (1) to 3 (n) and the server 4.

The Ethernet switch 1 includes a plurality of ports for interfacing with the clients 3 (1) to 3 (n) and the server 4, and the ports are PHY 41 (1) to PHY 41 (n + 1) in FIG. ). In other words, Ethernet switch 1
Has a function of sending out the frame to a predetermined port according to the destination address of the frame transmitted from the clients 3 (1) to 3 (n) and the server 4.

[1.2. Configuration of the transit time fixing device]
Next, a specific configuration of the transit time fixing device 2 that fixes the transit times of frames from the clients 3 (1) to 3 (n) and the server 4 will be described in detail.
As shown in FIG. 1, the transit time fixing device 2 includes signal lines 27 (1-1) to (n + 1), (2-1).
To (2-n + 1), Ethernet switch 1, client 3 (1) to 3 (n)
And a determination circuit 24 that detects a synchronization frame transmitted from the server 4.

  The determination circuit 24 includes a control circuit 25 as shown in FIG. 2, and the control circuit 25 has the following functions. Frame type determination means 25a for determining the frame type of the transmitted frame and frame control circuit 23 to be transmitted based on the destination address of the frame, and destination determination means 25b for outputting the frame to the specified destination (Corresponding to the destination specifying means). When the frame type determination unit 25a determines that the frame is a synchronization frame based on the destination address, the frame type determination unit 25a transmits a delay command to the frame control circuit 23 specified by the destination determination unit 25b, and determines that the frame is not a synchronization frame. In this case, a passage command is transmitted to the specified frame control circuit 23.

In addition, the transit time fixing device 2 delays the synchronization frame detected by the determination circuit 24 for a fixed time (fixed time) and then transmits it to the clients 3 (1) to 3 (n) and the server 4 as a frame control circuit 23 ( 1) to frame control circuit 23 (n + 1). The specific configuration of the frame control circuit 23 is described in [2.1. This will be described in detail in the item of “First operation example”.

Further, as shown in FIG. 1, PHY 22 (1) to PHY 22 (n + 1) as ports for interfacing with the clients 3 (1) to (n) and the server 4, and ports for interfacing with the Ethernet switch 1 are used. PHY21 (1) to PHY21 (n + 1)
It has.

[2.1. First operation example]
Next, a first operation example of the transit time fixing device 2 according to the present embodiment having the above-described configuration will be described below. Note that the frame configuration 1 transmitted from the client 3 such as the frame 101 and the frame 102 includes, for example, a destination address, a transmission source address, a frame type, a data part, and an FCS (check code) as shown in FIG.

  As will be described later, the synchronization frame and other frames (general frames) are distinguished from each other based on the frame type in the frame configuration, and processing for making the delay time constant is performed when the frame is the synchronization frame. That is, in the passage time fixing device 2, only the synchronization frame passes through the fixing device 2, and no delay processing is performed.

Below, with reference to FIG. 3 and 4, the process sequence of the passage time fixing apparatus 2 is shown according to a time series. Here, a case will be described in which a frame to be transmitted does not include a general frame and is a synchronization frame 101.
First, the frame 101 from the client 3 (1) is transmitted to the transit time fixing device 2 through the port PHY 22 (1) at the timing of the time chart 2 shown in FIG.

  Then, in the determination circuit 24 provided in the passage time fixing device 2, the frame type determination means 25a in the control circuit 25 determines the frame type of the frame 101 sent from the client 3 (1). Here, if the frame type determination means 25a determines that the frame 101 from the client 3 (1) is a synchronous frame, the frame control circuit 23 (n + 1) delays the frame 101 for a certain time. Give a command.

The destination determination unit 25b in the control circuit 25 acquires the destination address from the received frame 101, thereby specifying the frame control circuit 23 (n + 1) that is the target of the delay command. Specifically, since the frame control circuit 23 (n + 1) and the PHY 23 (2-n + 1) are set as the destination of the synchronization frame 101, the destination determination unit 25b sets the frame as a target for sending a delay command. The control circuit 23 (n + 1) is specified, and a delay command is issued to the frame control circuit 23 (n + 1).

  Here, as shown in FIG. 4, the frame control circuit 23 includes a FIFO 26. When a delay command is issued, the frame control circuit 23 accumulates a synchronization frame that requires this delay in the FIFO 26 for a certain period of time to elapse the delay time. . More specifically, the FIFO 26 includes a fixed time delay means 26a for delaying the synchronization frame for a fixed time, and the fixed time delay means 26a delays the synchronization frame for a fixed time.

  On the other hand, in the case of a frame for which delay processing is not performed, the control circuit 25 in the determination circuit 24 issues a frame passage command to the FIFO 26 and passes through the frame control circuit 23 without delaying for a predetermined time. That is, when the frame type determination means 25a in the control circuit 25 determines that the frame is not a synchronous frame, a frame passage command is issued, so that the delay processing by the fixed time delay means 26a is not performed, and the frame is It passes through the control circuit 23.

Therefore, as shown in FIG. 3, in the frame control circuits 23 (1) to (n + 1), the received synchronization frame 101 is delayed for a fixed time by the fixed time delay means 26a. The synchronous frame 101 is output onto the cable 31 (2-n + 1) through the PHY 22 (n + 1) corresponding to the specified frame control circuit 23 (n + 1) based on the above. That is, the frame control circuit 23 (n + 1) can delay the synchronization frame 101 for a fixed time, so that the transmission delay time can be fixed.

  The fixed time of the synchronization frame delayed by the FIFO 26, that is, the fixed time delayed by the fixed time delay means 26a differs depending on the transmission speed of the port used for frame transmission, and can be expressed as follows.

[Equation 1]
(Standard maximum frame length + α) / transmission speed However, the maximum delay time may be fixed as this delay time.

For example, the frame length is 8000 bytes (standard maximum frame length + α) and the transmission speed is 1 [Expression 2]
The delay time in the case of Gbps is as follows.
(8000 bytes * 8 bits) / 1G = 64μs

[2.2. Second operation example]
Next, a second operation example of the transit time fixing device 2 having the above configuration will be described below with reference to a time chart 3 shown in FIG. In the second operation example, an operation procedure when frames are transmitted to the transit time fixing device 2 in the order of the general frame 102 from the client 3 (2) and the synchronization frame 101 from the client 3 (1) will be described. .

  First, according to the time chart 3 of FIG. 5, the frame 102 from the client 3 (2) is transmitted to the transit time fixing device 2 through the PHY 22 (2). Then, the control circuit 25 in the determination circuit 24 determines the frame type of the frame 102 transmitted from the client 2. That is, it is determined whether the frame 102 received by the frame type determination means 25a in the control circuit 25 is a synchronous frame or not.

As described above, since the frame 102 is a general frame, the frame type determination unit 25a determines that it is not a synchronization frame. Also, the destination determination unit 25b specifies the frame control circuit 23 (n + 1) that is the transmission target based on the destination address of the frame 102. Here, since it is determined that the frame type determination unit 25a is a frame other than the synchronization frame, that is, a general frame, the frame type determination unit 25a determines the frame control circuit 23 (n + 1) specified by the destination determination unit 25b. In response to this, a pass command for the frame 102 is sent without giving a delay command.

As a result, the general frame 102 passes through the frame control circuit 23 (n + 1) specified by the destination determination means 25b and is output onto the cable 31 (2-n + 1). That is, the general frame 102 passes through the FIFO 26 without being delayed by the fixed time delay means 26a in the FIFO 26, and is output on the cable 31 (2-n + 1).

  Then, as shown in the time chart 3 of FIG. 5, the frame 101 from the client 3 (1) is transmitted to the transit time fixing device 2 through the PHY 22 (1). In the determination circuit 24 in the transit time fixing device 2, the frame type of the frame 101 transmitted from the client 3 (1) is determined by the frame type determination means 25 a in the control circuit 25.

As described above, since the frame 101 from the client 3 (1) is a synchronization frame, the frame type determination unit 25 a determines the frame 101 as the synchronization frame 101. The destination determination unit 25b in the control circuit 25 identifies the frame control circuit 23 (n + 1) to be transmitted based on the destination address of the synchronization frame 101. When the frame type determination unit 25a determines that the frame is the synchronization frame 101, the frame type determination unit 25a transmits a delay command for the frame 101 to the frame control circuit 23 (n + 1) specified by the destination determination unit 25b.

In the frame control circuit 23 (n + 1) for which the delay command has been issued, the fixed time delay means 26a in the FIFO 26 delays the synchronous frame 101 for a fixed time as shown in the time chart 3, and the synchronous frame in which the delay is completed. 101 is output on the cable 31 (2-n + 1). That is, the synchronization frame 101 is accumulated in the FIFO 26 for a certain time by the certain time delay means 26a, and is output on the cable 31 (2-n + 1) when this certain time elapses.

[2.3. Third operation example]
Next, a third operation example of the passage time fixing device 2 will be described below with reference to the time chart 4 of FIG. In the third operation example, an operation procedure in the case of transmitting the synchronization frame 101 from the client 3 (1) and the general frame 102 from the client 3 (2) to the transit time fixing apparatus 2 in this order will be described.

  In the third operation example, the frame control circuit 23 includes a delay frame determination unit 26b that determines whether or not there is a delayed frame in the frame control circuit 23. Further, when the delay frame determination unit 26b determines that there is a delayed frame, the general frame standby unit 26c (corresponding to the delay unit) waits for a frame other than the synchronization frame until the delay of the delayed frame is completed. Yes).

  First, as shown in the time chart 4 of FIG. 6, the frame 101 from the client 3 (1) is transmitted to the transit time fixing device 2 through the PHY 22 (1). When transmitted to the transit time fixing device 2, the control circuit 25 in the determination circuit 24 determines the frame type of the frame 101 from the client 3 (1). That is, the frame type determination means 25a in the control circuit 25 determines whether the frame 101 from the client 3 (1) is a synchronous frame or the other.

The destination determination unit 25b in the control circuit 25 identifies the frame control circuit 23 (n + 1) to be transmitted from the destination address of the frame 101. The frame type determining means 25a then sends the frame control circuit 23 (n +) specified by the destination determining means 25b.
A frame 101 delay command is issued to 1).

  Next, as shown in the time chart 4 of FIG. 6, the frame 102 from the client 2 (313) is transmitted to the transit time fixing device 2 through the PHY 22 (2). When the frame 102 from the client 3 (2) is transmitted to the transit time fixing device 2, the frame type determination means 25 a in the control circuit 25 of the determination circuit 24 determines the frame type of the frame 102.

Here, as described above, since the frame 102 from the client 3 (2) is a general frame, the frame type determination unit 25a determines that it is a frame other than the synchronization frame, that is, the general frame 102. The destination determination means 25b in the control circuit 25 identifies the frame control circuit 23 (n + 1) to be transmitted based on the destination address of the frame 102. The frame type determination unit 25a sends a frame 102 passing command to the frame control circuit 23 (n + 1) specified by the destination determination unit 25b.

Here, when the general frame 102 from the client 3 (2) is sent to the frame control circuit 23 (n + 1) specified by the destination determination means 25b, the delayed frame determination of the frame control circuit 23 (n + 1) is performed. The means 26b determines whether there is a delayed frame in the FIFO 26. As shown in the time chart 4 of FIG. 6, in this operation example, since the synchronization frame 101 transmitted from the previous client 3 (1) is in a delay of a predetermined time, the delay frame determination unit 26b causes the frame being delayed. 101 is determined to exist.

In this frame control circuit 23 (n + 1), since the previous synchronization frame 101 is being delayed, the general frame waiting means 26c converts the general frame 102 from the client 2 into the synchronization frame for a predetermined time as shown in FIG. Delay until the delay is complete. That is, the general frame 102 transmitted to the frame control circuit 23 (n + 1) is accumulated in the FIFO 26 until the delay of the previous synchronization frame 101 ends.

  Then, when the delay of the predetermined time of the synchronization frame 101 from the client 3 (1) is completed and output on the cable 31 (2-n + 1) through the PHY 22 (n + 1), the general frame standby means 70c The standby of the general frame 102 is also terminated, and the frame 102 is output on the cable 31 (2-n + 1) following the synchronization frame 101.

  According to the present embodiment as described above, since the synchronization frame can be delayed for a certain time by the frame control circuit, the transmission delay time can always be fixed with respect to the synchronization frame. Furthermore, since the difference in transmission delay time between the synchronization frames is not generated by the Ethernet switch, highly accurate sampling synchronization control can be realized. In addition, since it is not necessary to limit the frame length to a certain value or less, a large amount of information can be transmitted efficiently.

[Other Embodiments]
In addition, this invention is not limited to the above embodiments, The following embodiment is also included. That is, as shown in FIG. 7, the present invention also includes an embodiment in which the configuration of the determination circuit 24 and the frame control circuit 23 of the transit time fixing device 2 as described above is adopted in the Ethernet switch 1. As a result, it is possible to perform highly accurate sampling time synchronization control by the Ethernet switch 1 alone.

  In addition, in order to protect the power transmission line connecting the terminals based on the current information of the terminals, the protective relay device performs sampling synchronization between the terminals via the network and controls the transmission delay time between the terminals. A protection relay device transit time fixing device comprising: current type information from each terminal; and frame type determination means for determining whether a frame received via the network is a synchronous frame; and the frame type There is also provided a transit time fixing device for a protective relay device, comprising: a fixed time delay unit that delays transmission of the frame to the counterpart terminal for a fixed time when the determination unit determines that the frame is a synchronous frame. The present invention includes this embodiment.

DESCRIPTION OF SYMBOLS 1 ... Ethernet switch 2 ... Passing time fixing device 3 ... Client 4 ... Server 21 ... PHY (1)-(n + 1)
22 ... PHY (1) to (n + 1)
23 ... Frame control circuit 24 ... Determination circuit 25 ... Control circuit 25a ... Frame type determination means 25b ... Destination determination means 26 ... FIFO
26a ... definite time delay means 26b ... delay frame determination means 26c ... general frame standby means 27 ... signal lines (1-1) to (n + 1), (2-1) to (2-n + 1)
31 ... Cables (1-1) to (1-n), (2-1) to (2-n + 1)
41 ... PHY (1) to (n + 1)
70c: General frame waiting means 101: Frame (synchronous frame)
102 ... Frame (general frame)

Claims (18)

A protection relay that performs sampling synchronization between the protection relay devices via a network in order to protect the power system based on the electrical quantity information of the power system. Electric system,
Frame type determination means for determining whether a frame received from the protection relay device via the network is a synchronization frame;
Fixed time delay means for delaying transmission of the frame to the counterpart protection relay device for a fixed time when it is determined by the frame type determination means to be a synchronous frame;
A protective relay system comprising:   The protection relay system according to claim 1, wherein the fixed time delay means transmits a frame by FIFO.   The protection relay system according to claim 1 or 2, wherein the frame type determination unit determines a synchronization frame based on a frame type added to the frame by the protection relay device.   The protection relay system according to any one of claims 1 to 3, wherein the constant time delay means delays the frame for a fixed time longer than a time obtained by dividing the length of the frame by a transmission rate.   The said fixed time delay means passes the said frame, without delaying for a fixed time, when it determines with the said frame type determination means not being a synchronous frame, The any one of Claims 1-4 characterized by the above-mentioned. The protective relay system described in the paragraph.   The protection relay system according to claim 1, wherein the fixed time delay means is provided for each protection relay device. The frame includes destination address information for specifying the target fixed time delay means,
The protection relay system according to any one of claims 1 to 6, further comprising destination specifying means for specifying the fixed time delay means for each frame based on the destination address information. Delay frame determining means for determining whether or not there is the synchronization frame being delayed by the fixed time delay means;
A delay unit that delays a frame that is determined not to be a synchronization frame by the frame type determination unit when the delay frame determination unit determines that the synchronization frame being delayed exists;
The protective relay system according to any one of claims 1 to 7, further comprising:   9. The protective relay system according to claim 8, wherein the delay unit delays the delay of the synchronization frame until completion. A protection relay that performs sampling synchronization between the protection relay devices via a network in order to protect the power system based on the electrical quantity information of the power system. A method for fixing the transit time of an electric system,
A frame type determination step for determining whether a frame received from the protection relay device via the network is a synchronization frame;
A fixed time delay step for delaying transmission of the frame to the partner protection relay device for a fixed time when it is determined by the frame type determination step that the frame is a synchronization frame;
A method for fixing the transit time of a protective relay system, comprising:   The method of fixing a transit time of a protection relay system according to claim 10, wherein the predetermined time delay step transmits a frame by FIFO.   The method of fixing a transit time of a protection relay system according to claim 10 or 11, wherein the frame type determination step determines a synchronization frame based on a frame type added to the frame by the protection relay device.   The transit time of the protective relay system according to any one of claims 10 to 12, wherein the constant time delay step delays the frame for a predetermined time longer than a time obtained by dividing the length of the frame by a transmission rate. Fixing method.   The said fixed time delay step passes the said frame, without delaying for a fixed time, when it determines with the said frame type determination step not being a synchronous frame, The any one of Claims 10-13 characterized by the above-mentioned. The transit time fixing method of the protective relay system according to the item.   The method of fixing a transit time of a protection relay system according to any one of claims 10 to 14, wherein the predetermined time delay step is performed for each protection relay device. The frame includes destination address information for specifying the target fixed time delay step,
The transit time fixing of the protective relay system according to any one of claims 10 to 15, further comprising a destination specifying step that specifies the predetermined time delay step for each frame based on the destination address information. Method. A delay frame determination step for determining whether or not there is the synchronization frame being delayed by the predetermined time delay step;
A delay step of delaying a frame that is determined not to be a synchronization frame by the frame type determination step when it is determined by the delay frame determination step that the delayed synchronization frame exists;
The transit time fixing method for a protective relay system according to any one of claims 10 to 16, further comprising:   The method according to claim 17, wherein the delaying step delays until the delay of the synchronization frame is completed.

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