JP2010041899A - Protection relay system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protection relay system for performing synchronous control even among communication function parts mounted with only a general-purpose network control circuit without applying a special frame transmitting and receiving timing control circuit for Ethernet communication. <P>SOLUTION: The protection relay system is configured as follows. The communication function parts of the respective protection relay devices RY are constituted as the Ethernet communication function part EC and are connected with an Ethernet line network respectively. Data based on electrical quantity measured with each terminal as a protective target is transmitted and received mutually by passing through the Ethernet line network from the Ethernet communication function parts. The differential operation of electrical quantity data is performed in the protection control function part of the protection relay device to perform accident detection and protection of the protective target. The time server TS is connected to the Ethernet line network. Time synchronization is performed by the network synchronous protocol between the Ethernet communication function part EC of the protection relay device RY and the time server TS. The electrical quantity added with the synchronous time as a sampling address is communicated therebetween. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the present invention, the protection relay devices installed at each terminal are connected to each other by an Ethernet (registered trademark) network, and each protection relay device is operated based on the electric quantity data with time (time tag). The present invention relates to a protection relay system.

  One of the protection relay devices applied for the purpose of protecting transmission lines is a current differential relay device. This current differential relay device is a relay device of a type that identifies an internal accident when the vector sum of instantaneous current value data measured at each terminal of the transmission line is not zero, and when this is realized with a digital protective relay, The instantaneous current value data measured at each terminal is converted into digital data at a predetermined sampling timing, and the digital data is transmitted to the other terminal side by the PCM (Pulse Code Modulation) method via the dedicated serial communication line. The accident is determined by performing a differential operation between the instantaneous current value data transmitted from the terminal and the instantaneous current value data measured at its own terminal.

  What is necessary when performing transmission line protection by differential operation is that the instantaneous current value measurement timing at each terminal must be synchronized with high accuracy. Synchronizing this instantaneous current value measurement timing is generally called sampling synchronization (see, for example, Patent Document 1).

  Then, in order to realize sampling synchronization, the current differential relay device adds a sampling address indicating the electrical angle at the time of measurement to the current instantaneous value data measured by each terminal, and from the measured current instantaneous value of the own terminal and the counterpart terminal The calculation using current instantaneous value data having the same sampling address with the received current instantaneous value is performed.

  In the conventional sampling synchronization method in the current differential relay device, information frame communication such as fixing of frame transmission timing by hardware mechanism, stabilization of transmission line delay time by dedicated line, mechanism for latching / acquiring frame reception timing, etc. High-precision synchronization is realized by minimizing the fluctuation of the delay time that occurs in the system and making the mechanism capable of acquiring the synchronization correction element.

Hereinafter, a conventional power transmission line protection system using a current differential relay device will be described with reference to FIGS.
First, in FIGS. 7 and 8, these are both configuration diagrams of a conventional power transmission line protection system using a current differential relay device, in which FIG. 7 is a two-terminal protection system configuration and FIG. 8 is a three-terminal protection system configuration configuration. FIG.

  7 and 8, A, B, and C represent terminals of the transmission line TL. CTa, CTb and CTc are current transformers for detecting terminal currents installed at the terminals A, B and C, respectively. RY-A, RY-B, and RY-C are current differential protection relay devices installed at terminals A, B, and C, respectively, and a protection control function unit P including a main protection relay unit and a logic sequence unit; The serial control function unit SC is configured to transmit the output of the protection control function unit P to the opposite terminal and receive the signal transmitted from the opposite terminal.

  The protection control function part P, after sampling the instantaneous value of the current measured at its own terminal, determines whether it is an internal accident by performing a differential operation with the current instantaneous value data transmitted from the counterpart terminal, The serial transmission function unit SC transmits the sampling data obtained at the terminals A, B, and C to the opposing terminals via the communication lines t-ab, t-bc, and t-ca.

Next, the data communication operation in the conventional protection relay system will be described.
7 and 8, the serial transmission function unit SC of the protection relay devices RY-A, RY-B, and RY-C installed at each terminal has a communication frame configuration shown in FIG. And 12 frames as one super frame), and communicates with the counterpart terminal via the communication lines t-ab, t-bc and t-ca.

  Among the protection relay devices RY-A, RY-B and RY-C installed at each terminal, the protection relay device RY-A installed at the A terminal is a protection relay installed at the main station, the B terminal and the C terminal. Devices RY-B and RY-C are preset as slave stations. The slave station is set so as to be synchronized with the timing correction so as to be synchronized with the sampling timing of the master station.

  When a plurality of slave stations are configured as in the three-terminal configuration of FIG. 8, the protection relay device RY-B is arranged in order with the slave station 1 and the protection relay device RY-C is arranged in the slave station 2. -B) is synchronized with the master station (protection relay device RY-A), and then the slave station 2 (protection relay device RY-C) is synchronized with the slave station 1 (protection relay device RY-B). .

  When the establishment of the sampling synchronization is recognized, the sampling address synchronization between the terminals is established based on b5; SA synchronization flag in the control bit expansion example of FIG. Since the health of the system was confirmed by establishing synchronization of protection relays between terminals and monitoring various transmission failures, etc., the amount of electricity transmitted by the protection relay devices at each terminal and the amount of electricity measured at its own end Implement system protection control based on the data.

In data communication directed to these counterpart terminals, a communication line is arranged for each counterpart terminal as shown in FIG. 8, so that reception is performed during the communication frame as described in the communication frame format of FIG. There is no destination (partner device address) information. In addition, since the communication line is individually installed for each counterpart terminal, it is necessary to perform the frame transmission process and the frame reception process as many times as the counterpart terminal.
Note that the detailed technique of the sampling synchronization method and the synchronization establishment determination is described in detail in Patent Document 1 and will be omitted.

In the conventional current differential relay device described above, the limit of the communication data amount according to the adopted communication equipment and installation environment, restrictions on the terminal configuration (FIGS. 7 and 8), and a dedicated line for the protection relay device For reasons such as high costs, it is difficult to flexibly change or extend the system protection range.
In addition to this, the communication equipment that has been conventionally employed is heading toward the degeneration direction in view of future technological progress, and it is predicted that it will be difficult to perform equipment maintenance over a long period of time.

The limit of the communication data amount described above will be described in more detail with reference to FIG.
The communication speed of current communication facilities is 54 Kbps as a standard due to restrictions on communication equipment specifications such as communication lines and modulation / demodulation equipment. On the other hand, if the electric quantity data necessary for the current differential calculation, the electric quantity data transmission cycle, and communication frame defect test information (CRC code, fixed bit, etc.) are added, the electric quantity data that can be incorporated into one communication frame is very Very few. As countermeasures, optimization of the electrical data processing (filtering the measured raw data, compressing the bit length, disassembling / combining data that allows low-speed update) and the communication frame format for each protection system, Such measures are being implemented.

  In addition, instead of communication using a dedicated line, a form using a high-speed multiplex line has also been put into practical use, and in this case, the problem of the dedicated line is eliminated, but the communication frame multiplexing processing causes the communication frame transmission and reception timing to be It is not stable, so it is difficult to adopt conventional sampling synchronous control.

  For this reason, in the case of the form using the high-speed multiplex line, as shown in FIG. 9, the radio wave of the GPS satellite S is received by the GPS receiver R installed in the current differential relay device of each terminal A, B, By synchronizing the terminals A and B at the time S, a system in which the sampling timing is matched is realized.

  However, this GPS system has some operational problems. For example, (i) it is necessary to secure an antenna installation place where radio wave reception is stable and good, (ii) high cost of the GPS device itself, (iii) reception of the GPS receiver device due to radio wave effects from other devices or intentional radio wave interference Impossibility, etc. are conceivable, and in order to solve these problems, there is a drawback that burdens and restrictions are imposed on operational aspects, economic aspects, and stability.

  In order to solve such a problem of the GPS synchronization system, and for the purpose of switching the communication line equipment to the high-speed line network which has been widely spread in recent years, the inventors have developed a sampling synchronization control system to which wide area Ethernet is applied. The prototype was manufactured (for example, refer nonpatent literature 1).

When the sampling timing synchronization is corrected by the sampling synchronization control system introduced in Non-Patent Document 1, synchronization with a very high accuracy such as a deviation of 100 to 500 nanoseconds can be realized.
Japanese Patent Laid-Open No. 2-155421 2008 Annual Conference of the Institute of Electrical Engineers of Japan (March 21, 2008), Proceedings [6] Power System, Paper No. 6-302, “Development of sampling synchronous control using wide area Ethernet”

  However, the sampling synchronization control system introduced in Non-Patent Document 1 adds a special communication control mechanism, such as communication frame transmission timing control and incoming timing detection, to the network control circuit as shown in FIG. 11 later. For this reason, synchronization correction cannot be performed with a device in which only a general-purpose network control circuit is mounted. That is, in the system configuration of Non-Patent Document 1, there is a restriction that an equivalent special network control circuit must be installed in all devices that require synchronization correction.

  In general, the sampling timing shift between devices is obtained by communicating frame transmission timing and frame reception timing as time information (count value) frames. At this time, the waiting time from the frame transmission processing by the software until the frame is actually transmitted on the communication line and the waiting time from when the frame arrives until the frame reception processing by the software actually operates are the actual frames. It appears as an error from the outgoing / incoming timing, and these waiting times vary depending on the operating state of the software, making it difficult to perform highly accurate synchronization correction.

  In order to realize highly accurate sampling synchronization, in the sampling synchronization control system 300 introduced in Non-Patent Document 1, frame transmission / reception timing control by a hardware mechanism is added to a general-purpose network control circuit 310 as shown in FIG. A circuit 320 is added to eliminate the synchronization error due to the above-described variation in waiting time that causes an error.

  Hereinafter, the frame transmission / reception timing control of Non-Patent Document 1 will be described with reference to FIG. The CPU 301 executes a plurality of software such as communication processing and protection control processing. Here, the description will focus on communication processing.

  The CPU 301 stores the generated transmission frame in the transmission buffer memory 311 and issues a transmission command to a network interface controller (NIC) 313. In response to a transmission command from the CPU 301, the NIC 313 takes out the transmission frame stored in the transmission buffer memory 311, converts it into an Ethernet frame by the MAC layer control circuit 314, and further encodes this Ethernet frame by the physical layer control circuit 315. It is converted into data and sent out of the general-purpose network control circuit 310. At this time, the data transmission timing depends on the operating conditions of the CPU 301 and the NIC 313.

  Code data sent from the general-purpose network control circuit 310 is converted back to an Ethernet frame by the physical layer control circuit 321 of the frame transmission / reception timing control circuit 320 and stored in the transmission frame holding buffer memory 322.

  The Ethernet frame stored in the transmission frame holding buffer memory 322 is taken out by the transmission timing control circuit 323 which starts operation by the pulse signal output from the sampling pulse transmission circuit 302 and is input to the physical layer control circuit 324. The data is converted back into code data and sent to the communication line t via the connector (RJ45) 325. That is, the transmission control is performed so that the timing finally transmitted to the communication line t is equivalent to the timing of the sampling pulse transmission circuit 302.

  The purpose of the re-conversion to the Ethernet frame by the physical layer control circuit 321 of the frame transmission / reception timing control circuit 320 is that the transmission timing control circuit 323 needs to recognize the size and type of the transmission frame stored in the transmission frame holding buffer memory 322. This is because it is difficult to use code data as it is. Further, the NIC 313 in the general-purpose network control circuit 310 is generally one in which a MAC layer control circuit 314 and a physical layer control circuit 315 are integrated.

Next, the path and mechanism when receiving a communication frame will be described.
Code data input from the counterpart terminal via the communication line t and the connector (RJ45) 325 is converted into an Ethernet frame by the physical layer control circuit 324 in the frame transmission / reception timing control circuit 320 and received by the received frame type verification circuit 326. The type of received frame and the source address are determined. If it is a synchronous frame, a signal is output to the counter counting circuit 332 and the counter value is latched. The latched counter value is information for obtaining an accurate frame reception timing. Reference numeral 331 denotes a crystal oscillator.

  In the apparatus described in Non-Patent Document 1, the received frame type verification circuit 326 transmits / receives a received frame converted into an Ethernet frame by the physical layer control circuit 324 via the physical layer control circuit 321 as shown in FIG. The signal is output to the outside of the timing control circuit 320 and input to the general-purpose network control circuit 310.

  In the general-purpose network control circuit 310, the physical layer control circuit 315 converts the code data into an Ethernet frame, and then stores it in the reception buffer memory 312 via the MAC layer control circuit 314.

The received frame is extracted from the reception buffer memory 312 by the communication software executed by the CPU 301 and processed by the CPU 301. The CPU 301 can recognize the occurrence of a received frame by referring to an internal register of the NIC 313 or by using an interrupt signal for generating a received frame from the NIC 313. In any case, the reception buffer memory 312 receives the received frame. It takes time until the CPU 301 reads the received frame from the reception buffer memory 312 after the frame is stored. However, since the reception timing of the synchronization frame is latched as a count value by the counter counting circuit 332, an accurate reception timing is required.
Sampling synchronization correction is performed by controlling the sampling pulse transmission circuit 302 based on the synchronization frame and the latch count value.

  As described above, in order to realize the sampling synchronization control system 300 introduced in Non-Patent Document 1, the frame transmission / reception timing control circuit 320 shown in FIG. 11 is necessary, and this is realized only by the general-purpose network control circuit (NIC) 310. Can not. Further, in order to be able to refer to the frame arrival timing by communication software, it is necessary to cooperate (bus access) with the CPU 301 on which the software operates, and the frame transmission / reception timing control circuit 320 is added to the general-purpose network control circuit 310. Easy expansion is not possible. For this reason, it must be a special communication board to which the above mechanism is added.

  On the other hand, even if the sampling synchronization accuracy is acceptable even if the accuracy is coarser than 10 to 20 microseconds or more, the communication device based on a general-purpose network control circuit without using the above mechanism can also perform synchronous control. Is possible.

  Therefore, the present invention has an object to provide a protection relay system capable of performing synchronous control between communication devices mounted only with a general-purpose network control circuit without applying a special frame transmission / reception timing control circuit for Ethernet communication. It is what.

In order to achieve the above object, according to the first aspect of the present invention, the communication function unit of the protection relay device installed at each terminal to be protected is configured as an Ethernet communication function unit and connected to the Ethernet network. , By transmitting and receiving data based on the electric quantity measured at each terminal to be protected to and from the Ethernet communication function part via the Ethernet network, the protection control function part of the protection relay device transmits the electric quantity data. A protection relay system that performs differential operation and protects the object to be protected.
The Ethernet communication function unit of the protection relay device is set to operate in a client mode with a time synchronization protocol,
A time server set to operate in a server mode with a time synchronization protocol similar to that provided in the Ethernet communication function unit is connected to the network,
The time server and the Ethernet communication function unit of the protection relay device are time-synchronized by the time synchronization protocol, and the synchronization time is added to the electrical quantity data as a sampling address.

  According to the present invention, a protection relay system in which an Ethernet network is applied to the communication line of the protection relay can be realized, and it is not necessary to maintain the communication speed and communication frame structure of the conventional protection relay system. The device information can be communicated to the other terminal, so that various protection control systems can be constructed, and facility maintenance is facilitated by using general-purpose network facilities and environments.

  In addition, since the sampling address is generated from the time stamp (device time information), the special communication procedure performed as the conventional sampling address synchronization is unnecessary, and the time synchronization between the protection relays is also 1: 1 with the time server. Therefore, the time from the start of the device to the sound operation of the protection function is shortened.

  In addition, the time stamp used for time synchronization is for searching for the measurement electrical angle coincidence, and the time value managed by the time server does not need to be synchronized with the standard time. A system protection system can be constructed with any of the above network configurations.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is a diagram illustrating an example of a network connection configuration of a protection relay system according to an embodiment of the present invention, FIG. 2 is a diagram illustrating an example of an Ethernet communication function unit according to the present embodiment, and FIG. 3 is a communication frame format between terminals. FIG. 4 is a diagram showing an example of a frame format when electric quantity data is communicated by UDP / IP, and FIG. 5 is a communication frame structure of a time synchronization protocol applied to time synchronization between terminals. FIG. 6 shows the relationship between the time synchronization time stamp and the sampling address.

(System configuration)
First, the protection relay system according to the present embodiment will be described with reference to FIG.
The protection relay system according to this embodiment is an Ethernet as a communication device that transmits and receives protection control function units P and terminal electrical quantity data to and from a partner terminal at each of the terminals A, B, and C of the three-terminal transmission line TL to be protected. (Ethernet) It is configured by installing protective relay devices RY-A, RY-B, and RY-C configured from the communication function unit EC.

  The Ethernet communication function units EC of the protection relay devices RY-A, RY-B, and RY-C are connected to the Ethernet network E-NET via the Ethernet communication lines ta, tb, and tc, respectively. The time server TS is connected to the Ethernet line network E-NET via an Ethernet communication line ts.

  The communication speed of the Ethernet network E-NET does not matter, but high-speed communication such as gigabits has less communication delay and can ensure high synchronization accuracy. Therefore, high-speed communication is preferable.

  Here, the time server TS incorporates a general “time synchronization protocol” used in devices connected to a network such as NTP (Network Time Protocol) and SNTP (Simple NTP) in a general-purpose computer. And is configured to operate in server mode.

  On the other hand, the Ethernet communication function units EC of the protection relay devices RY-A to RY-C installed at the terminals A to C have the same “time synchronization protocol” as that of the time server TS and operate in the client mode. Is set to

  Note that the “time synchronization protocol” is known, for example, as (RFC958 (Network Time Protocol)), and in the present invention, the time synchronization method is not questioned, so the description thereof will be omitted.

  Next, an example of the configuration of the Ethernet communication function unit EC of the protection relay device RY provided at each of the terminals A, B, and C will be described with reference to FIG. Will be described. Since the protection control function part P is not particularly different from the conventional current differential operation part, description thereof is omitted.

  The Ethernet communication function unit EC of the protection relay device RY shown in FIG. 2 includes a network control circuit 310 having the same configuration as the general-purpose network control circuit of the conventional example shown in FIG. 11 and an Ethernet communication driver 200 configured by communication software. I have.

  The network control circuit 310 includes a NIC 313 having a MAC layer control circuit 314 and a physical layer control circuit 315, a transmission buffer memory 311, a reception buffer memory 312, and a connector (RJ45) 325. Here, the MAC layer control circuit 314 and the physical layer control circuit 315 are configured to be incorporated in, for example, one communication control LSI.

  In the network control circuit 310, the transmission buffer memory 311 stores the transmission frame (same as the communication frame) generated by the transmission processing unit 201 of the Ethernet communication driver 200, and temporarily saves until the NIC 313 starts transmission processing. Used as a buffer. On the other hand, the reception buffer memory 312 stores a reception frame (same as a communication frame) output from the NIC 313, and is used as a temporary save buffer until the reception processing unit 202 of the Ethernet communication driver 200 starts extraction processing.

  Since the Ethernet communication function unit EC is configured as described above, a transmission frame generated by the transmission processing unit 201 of the Ethernet communication driver 200 taking in the electric quantity data output from the protection control function unit P (FIG. 3 described later). 3a to 3f or 4a to 4f in FIG. 4 are temporarily stored in the transmission buffer memory 311 and are taken into the NIC 313 from the transmission buffer memory 311 by requesting the NIC 313 to start transmission.

  The NIC 313 converts the captured transmission frame into an Ethernet frame by the MAC layer control circuit 314, and then converts it into code data by the physical layer control circuit 315, and then transmits the data to a partner (not shown) via the connector (RJ45) 325 and the communication line t. Sent to the terminal.

On the other hand, the code data of the counterpart terminal received by the network control circuit 310 from the counterpart terminal (not shown) via the communication line t is input to the NIC 313 via the connector (RJ45) 325 and code-converted by the physical layer control circuit 315. Thereafter, the frame is converted into a reception frame by the MAC layer control circuit 314 and stored in the reception buffer memory 312, and the generation of the reception frame is notified to the reception processing unit 202 of the Ethernet communication driver 200 by an interrupt signal. The reception processing unit 202 activated by the interrupt signal takes out the received frame from the reception buffer memory 312 and starts processing, and sends the processing result to the protection control function unit P.
In the protection control function unit P, the protection control calculation is performed using the electric quantity data of the own terminal and the electric quantity data of the counterpart terminal input from the Ethernet communication driver 200.

(Composition of communication frame)
Next, referring to FIG. 3, the first example of the format of a transmission frame (communication frame) generated by the transmission processing unit 201 of the Ethernet communication driver 200 taking in the electric quantity data measured by the protection control function unit P Will be described.

  In FIG. 3, the communication frame employed in the present embodiment has a structure similar to that of an Ethernet frame, and includes a “destination address field (6 bytes)” 3a, a “source address field (6 bytes)” 3b, and a “type field (2 bytes)”. 3c, “Sampling address field; SA (8 bytes)” 3d, “Electric quantity data field (38 to 1492 bytes)” 3e, and “Frame check sequence code field; FCS (4 bytes)” 3f, a total of 6 fields.

  Among these, the type field 3c is assigned a type number of a protocol other than a predetermined type number or a protocol that is not used in the network, thereby enabling discrimination between the “electric quantity data communication frame” and other frames.

  The sampling address (SA) 3d indicates the time (timing) when the electric quantity data is measured, and is a data index for performing a differential protection operation between the electric quantity data of the own terminal and the electric quantity data received from the counterpart terminal. It becomes.

  Note that the sampling address (SA) 3d of each of the terminals A to C needs to be synchronized before starting the differential protection operation. The electric quantity data 3e is an instantaneous current value or a voltage quantity measured at its own terminal, but the type of information and the bit length differ depending on the protection section and method, and are not limited. can not touch.

  Next, referring to FIG. 4, a second example of the format of a transmission frame (communication frame) generated by the transmission processing unit 201 of the Ethernet communication driver 200 taking in the electric quantity data output from the protection control function unit P Will be described. In FIG. 4, a frame structure in the case where electricity data is communicated between the terminals A to C using UDP / IP will be described.

  In FIG. 4, the UDP / IP communication frame includes a “destination address field (6 bytes)” 4a, a “source address field (6 bytes)” 4b, a “type field (2 bytes)” 4c, a “sampling address field; SA (8 bytes). "4d", "Electric quantity data field (10 to 1464 bytes)" 4e and "Frame check sequence code field; FCS (4 bytes)" 4f, "IP header (20 bytes)" 4g and "UDP header (8 bytes)" 4h It consists of a total of 8 fields.

  When the terminals A to C communicate with each other by UDP / IP, the communication between terminals can be performed not by “MAC address” recognition but by recognition of “IP address” + “port number”. In addition, since the checksum test of the received frame is performed in the IP layer and the UDP layer, the reliability of the received electric quantity data is improved. Also, depending on the software or hardware configuration of the Ethernet communication function unit, there is a case where a special code cannot be incorporated into the type field as shown in FIG. 3, but even in such a case, it can be easily handled by communicating with UDP / IP. It is.

  Next, a communication frame structure of an NTP time synchronization protocol applied to time synchronization between terminals A to C will be described with reference to FIG. Note that the frame structure of the NTP time synchronization protocol itself is well known, and in the present invention, the time synchronization method is not limited, so detailed description will be omitted.

  In FIG. 5, the communication frame of the NTP time synchronization protocol includes “destination address (6 bytes)” 5a, “source address (6 bytes)” 5b, “type (2 bytes)” 5c, “frame check sequence code; FCS (4 bytes)”. "5f", "IP header (20 bytes)" 5g, "UDP header (8 bytes)" 5h, and "NTP data (48 bytes)" 5k, a total of 7 fields.

(Function)
Regarding data communication in the conventional three-terminal protection relay system, as already described with reference to FIG. 8, the protection relay devices RY-A, RY-B, and RY-C of the terminals A, B, and C are previously installed. The master station / slave station is set, and the slave station corrects the timing and synchronizes with the sampling timing of the master station. In the case of a plurality of slave stations such as a three-terminal configuration, the slave station 1 and the slave station 2 are arranged in order, and the slave station 1 synchronizes with the master station, and then the slave station 2 synchronizes with the slave station 1 in order. When the establishment of the sampling synchronization is recognized, the sampling address synchronization between the terminals is established based on the SA synchronization flag (control bit b5 in FIG. 10B). The protection relay devices RY-A to RY-C of each terminal transmit to each other after confirming that the system is healthy by establishing various synchronizations of the protection relays between terminals and various monitoring such as transmission failures. System protection control was performed based on the amount of electricity data and the amount of electricity measured at its own end.

  On the other hand, in data communication according to the embodiment of the present invention, for example, in FIG. Each of the protection relay devices RY-A, RY-B, and RY-C performs time synchronization using the network synchronization protocol with the time server TS from the start, so that the protection relay devices at each terminal can be internally connected. Time can be synchronized.

Next, with reference to FIG. 6, the use of a time stamp that has been established and acquired by time synchronization will be described.
In FIG. 6, the time stamp (synchronization time) obtained from the time server TS via the Ethernet network E-NET, the Ethernet communication driver 200 of the Ethernet communication function unit EC, and the UDP / IP layer by the network synchronization protocol processing unit 401 is The unit is converted and stored in the timer counter 402 as the internal time of the protection relay device RY in milliseconds.

  The timer counter 402 is a sampling address of electric quantity data (3e in FIG. 3 and 4e in FIG. 4) measured by a sampling processing unit (electric quantity measuring unit) 403 activated at a predetermined cycle based on the sampling pulse transmission circuit 404. Adopted as SA (3d in FIG. 3, 4d in FIG. 4) (SA value adopted). Further, the internal time of the protection relay device RY is updated by adding the start cycle (time width) of the sampling pulse transmission circuit 404 to the timer counter value (adding the sampling cycle time).

  And after the time when it can be confirmed that the system is sound by various types of monitoring such as time synchronization establishment of the protection relay device RY-A and transmission failure, it is between the protection relay devices RY-B and RY-C of each terminal. The current differential protection calculation is performed based on the electrical quantity data transmitted to each other and the electrical quantity data measured at its own end.

  In the present embodiment, as shown in FIG. 1, all terminals are connected to one Ethernet network (E-NET). Therefore, as shown in FIG. 3 or FIG. By adding the “destination address” 3a or 4a, it is possible to determine whether or not the received frame is a reception frame (electric quantity data) that is valid at its own terminal.

  Also, frame reception processing needs to be performed as many as the number of counterpart terminals in the same way as conventional protection relays. However, for frame transmission processing, “destination address” is distributed as a multicast address or broadcast address, so that one frame transmission is performed. It can be distributed to all counterpart terminals by processing.

  Here, when a plurality of protection relays with different protection intervals are connected to one network, multicast distribution can be performed so that the communication frame is not distributed to the protection relay device in another protection interval. Broadcast distribution may be used as long as the network is closed in one protection section as shown in FIG.

(effect)
As described above, according to the embodiment of the present invention, a protection relay system in which a network (Ethernet line network) is applied to the communication line of the protection relay can be realized, and the communication speed and communication frame structure of the conventional protection relay device can be realized. Maintenance is no longer required, and a greater amount of electricity information and device information can be communicated to the other terminal, enabling the construction of various protection control systems and the use of general-purpose network equipment and environments. Equipment maintenance is also easy.

  In addition, since the sampling address is generated from the time stamp (device time information), a special communication procedure performed as conventional sampling address synchronization is unnecessary, and time synchronization between the protection relay devices is also performed with the time server TS. Since the operation is performed on a one-to-one basis, the time from the start of the device to the sound operation of the protection function unit P can be shortened.

  Further, the time stamp used for time synchronization is for searching for coincidence of the measured electrical angle, and the time value managed by the time server TS does not need to be synchronized with the standard time, and is a local network dedicated to the protection relay system. A system protection system can be constructed with either a configuration or a wide-area network configuration.

The line protection system block diagram of the 3 terminal by the current differential relay of the Ethernet connection by embodiment of this invention. The figure which shows an example of the Ethernet communication function part by embodiment of this invention. The figure which shows the example of a communication frame format between terminals. The figure which shows the example of a communication frame format between terminals at the time of UDP / IP communication application. The figure which shows the example of a communication frame format of an NTP time synchronous protocol. The figure which shows the relationship between a time synchronous time stamp and a sampling address. The system diagram of a two-terminal system protection system using a conventional current differential relay. FIG. 3 is a configuration diagram of a three-terminal system protection system using a conventional current differential relay. The line protection system block diagram of the 2 terminal by the current differential relay which employ | adopted GPS synchronization. The figure which shows the example of a communication frame format applied with the conventional current differential relay. The block diagram of the conventional network control circuit.

Explanation of symbols

  A, B, C ... terminals, RY-A, RY-B, RY-C ... protection relay device, P ... protection control function unit, EC ... Ethernet communication function unit, E-NET ... Ethernet network, TS ... time server , T ... communication line, 200 ... Ethernet communication driver, 201 ... transmission processing unit, 202 ... reception processing unit, 310 ... network control circuit, 311 ... transmission buffer memory, 312 ... reception buffer memory, 313 ... NIC, 314 ... MAC layer Control circuit, 315, physical layer control circuit, 325, connector (RJ45).

Claims (3)

The communication function part of the protection relay device installed at each terminal to be protected is configured as an Ethernet communication function part and connected to the Ethernet network respectively, and data based on the amount of electricity measured at each terminal to be protected A protection relay system that performs differential operation of the electrical quantity data in the protection control function unit of the protection relay device by mutual transmission and reception by the Ethernet communication function unit via the Ethernet line network to protect the protection target Because
The Ethernet communication function unit of the protection relay device is set to operate in a client mode with a time synchronization protocol,
A time server set to operate in a server mode with a time synchronization protocol similar to that provided in the Ethernet communication function unit is connected to the network,
A protection relay system, wherein the time server and the Ethernet communication function unit of the protection relay device are time-synchronized by the time synchronization protocol, and the synchronization time is added to the electrical quantity data as a sampling address.   The differential calculation is performed with the electrical quantity information in which the measured electrical angles of the own terminal and the counterpart terminal coincide with each other by generating a sampling address based on the time stamp measured by the time synchronization protocol of the time server. The protection relay system according to 1.   An Ethernet communication function unit of the protection relay device is connected to the Ethernet network, and includes a network control circuit including a network interface controller, a transmission buffer memory, a reception buffer memory, and a connector, the network control circuit and the protection control function unit, The protection relay system according to claim 1, further comprising: an Ethernet driver that is connected between the two and performs transmission processing and reception processing.

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