JP2018102043A - Protection relay system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protection relay system using a general-purpose communication device.SOLUTION: Protection relays 1A to 1C include a transmission and sampling synchronization control section 5 for synchronizing sampling timing of an electric quantity of a system at each terminal among the protection relays 1A to 1C. The transmission and sampling synchronization control section 5 synchronizes the sampling timing based on a 1 PPS synchronous clock signal received from switching HUBs 2A to 2C. The switching HUBs 2 A to 2 C are synchronized in time and transmit sampling packet data including electric quantity data necessary for relay calculation to the protection relays 1 A to 1 C. The protection relays 1 A to 1 C that receive the data execute a relay calculation.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a protection relay system using transmission.

  Mainly, in a PCM (pulse code modulation) current differential protection relay device, protection relays (protection relays) provided at each terminal of the transmission line are connected to each other by a dedicated device and an optical fiber.

  Here, the amount of electricity sampled at the same time by each terminal is transmitted and received by a protection relay, and a system fault is detected by calculating the difference current. For example, Patent Document 1 proposes a technique for controlling the timing of time synchronization when the time synchronization specified in IEEE 1588 is used in combination with the protection relay.

  FIG. 3A shows an application example of the four-system power transmission system of Patent Document 1. This power transmission system includes power transmission lines L1, L2, and L3 provided between four terminals A, B, C, and D, and a circuit breaker CB and a current transformer CT provided in each of the terminals A to D. Yes. This current transformer CT detects the current I at each of the terminals A to D, and a closing command signal or a tripping command signal is given to the circuit breaker CT.

  A master unit M is installed at the terminal A, and a slave unit S is installed at the terminals B to D (in the figure, the slave units SB to SD are shown for the terminals B to D). Transmission paths 161 to 163 are provided between the master unit M and the slave units SB to SD. The master unit M corresponds to the master side that transmits a time signal in accordance with the IEEE 1588 standard, and the slave units SB to SD correspond to the slave side that receives the time signal and corrects the time.

  Each unit M, SB to SD takes in the current I of the terminals A to D and the contact information X of the circuit breaker CB (shown as currents IA to ID and contact information XA to XD in accordance with the terminals A to D in the figure). The slave units SB to SD transmit the captured information to the master unit M via the transmission paths 161 to 163.

  In the master unit M, differential calculation is performed based on the information of the currents IA to ID at the terminals A to D, and finally, the pulling is performed from the units M and SB to SD to the circuit breakers CB of the terminals A to D. Release command X is given.

  In this way, the master / slave-related units M and SB to SD are arranged corresponding to the terminals A to D of the transmission lines L1 to L3, and the transmission lines 161 to 163 are connected between them to protect the transmission lines. Configures a current differential protection relay system.

JP2011-200100A JP 2014-64396 A

  (1) FIG. 3B shows the configuration of the master unit M of Patent Document 1. Here, the master unit M includes the CUP 210, the contact control unit 220, the A / D conversion unit 230, the protocol control unit 240, the reception units 251 to 253, the transmission unit 260, the physical layers 271 to 273, the time synchronization unit 280, and the cycle generation unit. 290. The slave units SB to SD include the above-described configurations 210 to 290 and are configured in substantially the same manner.

  The protocol control unit 240 creates a data structure of various frames, outputs transmission protocol data 241 to the transmission unit 260, and inputs reception protocol data 254 to 256 from the reception units 251 to 253.

  The transmission unit 260 outputs transmission data 261 to the slave units SB to SD via the physical layers 271 to 273, and the reception units 251 to 253 similarly receive data 274 from the slave units SB to SD via the physical layers 271 to 273. Enter ~ 276. The physical layers 271 to 273 perform transmission through transmission paths 161 to 163 by performing conversion into electric signals that can be transmitted.

  (2) In constructing the protection relay system of Patent Document 1, it is necessary to install the units M and SB to SD at the terminals A to D. That is, a dedicated device such as each of the units M and SB to SD has to be prepared, and there has been a problem in the cost of introducing the system.

  In particular, in order to execute data transmission / reception with the slave unit S, the master unit M requires a physical layer corresponding to the number of slave units S, and there is a possibility that the expansion of the slave units S may be hindered.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a protection relay system using a general-purpose communication device instead of a dedicated device.

  The present invention connects a protection relay provided at each terminal of a power system through a network synchronized through a time-synchronized relay device, and performs a relay operation by sampling the amount of electricity of the system at each terminal by each protection relay. With respect to the protection relay system, each protection relay includes a transmission / sampling synchronization control unit that synchronously controls the sampling timing between the protection relays.

  As an aspect of the transmission / sampling synchronization control unit, the sampling timing can be synchronized based on a clock signal received from the relay device.

  The relay device is preferably time synchronized according to the IEEE 1588 standard. In addition, it is preferable that sampling packet data including electrical quantity data of a terminal provided with each protection relay is transmitted and received between the protection relays via the relay device. In this case, the relay calculation is executed based on the amount of electricity included in the sampling packet data.

  The sampling packet data may include a reference clock ID that identifies the relay device having the reference clock for time synchronization, and accuracy determination information that indicates normality / abnormality of time synchronization of the relay device.

  In this case, the relay device further transmits a synchronization clock signal indicating whether or not time synchronization is within a target accuracy between the relay devices to the protection relay. In addition, the protection relay includes a case where the synchronous clock signal is not within the target accuracy, a case where the reference clock ID included in each sampling packet data does not match, and a case where the accuracy determination information included in the sampling packet data is abnormal. And relay lock.

  According to the present invention, it is possible to provide a protection relay system using a general-purpose communication device instead of a dedicated device.

1 is an overall configuration diagram of a protection relay system according to an embodiment of the present invention. The detail figure of the protection relay and switching HUB. (A) is the whole block diagram of patent document 1, (b) is a detailed drawing of the master unit of (a).

  Hereinafter, a protection relay system according to an embodiment of the present invention will be described. Here, the same components as those in Patent Document 1 are described with the same reference numerals.

≪Configuration example≫
A configuration example of the protection relay system will be described with reference to FIGS. 1 and 2. FIG. 1 shows an application example of the protection relay system to a three-terminal power transmission system. Here, the protection relays 1 provided at the respective terminals A to C of the transmission lines L1 and L2 are respectively connected via the switching HUB2, and a current differential protection relay device for protecting transmission lines is provided as in Patent Document 1. It is configured. In FIG. 1, protection relays 1A to 1C and switching HUBs 2A to 2C are shown in accordance with the terminals A to C.

  The protection relay 1 and the switching HUB 2 are installed for each of the terminals A to C, and transmission lines 161 to 163 are provided between the switching HUBs 2. The transmission lines 161 to 163 are not expensive dedicated transmission lines but inexpensive high-speed general-purpose transmission lines such as Ethernet (registered trademark).

  Each terminal A to C is provided with a circuit breaker CB and a current transformer CT. The current transformer CT detects the current I at each of the terminals A to C, and gives an on / off command signal from each protection relay 1 to the circuit breaker CB. Moreover, each protection relay 1A-1C takes in the electric current I of the terminals AC detected by the current transformer CT, and the contact information X of the circuit breaker CB (in FIG. Accordingly, currents IA to IC and contact information XA to XC are indicated.)

  The protection relay 1 and the switching HUB 2 are installed for each of the terminals A to C, and transmission lines 161 to 163 are provided between the switching HUBs 2. The transmission lines 161 to 163 are not expensive dedicated transmission lines but inexpensive high-speed general-purpose transmission lines such as Ethernet (registered trademark).

  Moreover, each protection relay 1A-1C takes in the electric current I of the terminals AC detected by the current transformer CT, and the contact information X of the circuit breaker CB. In FIG. 1, currents IA to IC and contact information XA to XC are shown in accordance with the terminals A to C.

  The switching HUBs 2A to AC may be layer 2/3 switches, and have a PTP (Precision Time Protocol) time synchronization function defined in IEEE 1588. That is, a control function for automatically selecting a PTP master / slave is provided, a reference clock is selected from the switching HUBs 2A to 2C, and the selected switching HUB2 becomes the master.

  After this master / slave relationship is established, a “Sync message (synchronization message)”, “Follow_up message (synchronization message)”, “Delay_req message (delay request message)”, and “Delay_resp message (delay response message) are established between the master and slave. "Is exchanged.

  Based on the transmission / reception times of the “Sync message”, “Follow_up message”, and “Delay_req message”, the message round-trip delay time and time difference (clock offset) are calculated, and the slave time is synchronized with the master time. Is done.

  As shown in FIG. 2, the protection relays 1 </ b> A to 1 </ b> C are turned on or off with respect to the input unit 3 where the current information detected by the current transformer CT is input and A / D converted, and the circuit breaker CB. An output unit 4 that outputs a command signal; information necessary for sampling synchronization (hereinafter referred to as sampling synchronization information); a transmission / sampling synchronization control unit 5 that controls transmission / reception of D1 and D2, and current information of the input unit 3 An arithmetic unit (for example, CPU) 6 that executes a relay operation based on the sampling synchronization information is included.

  The sampling synchronization information D1 includes a 1PPS synchronization clock signal necessary for the protection relays 1A to 1C to synchronize the sampling timing, and a synchronization clock indicating whether the time synchronization is within the target accuracy between the switching HUBs 2A to 2C. And an abnormal output signal for notifying various abnormalities of the switching HUBs 2A to 2C corresponding to the protection relays 1A to 1C, respectively.

  The sampling synchronization information D2 includes PTP information packet data related to time synchronization between the switching HUBs 2A to 2C and sampling packet data such as electric quantity data necessary for the relay calculation of the calculation unit 6. Here, the PTP information packet data is transmitted from the switching HUB 2 to the protection relay 1 every second, and includes the own clock ID indicating the ID of the internal clock of the switching HUB 2 that transmits the data to the protection relay 1.

  Sampling packet data is transmitted and received between the protection relays 1A to 1C via the switching HUBs 2A to 2C. This sampling packet data has a frame synchronization section, an electric quantity section, and a sub-communication section (not shown).

  The frame synchronization unit includes the own clock ID, a reference click ID indicating the ID of the switching HUB 2 selected as the reference clock, operation mode information indicating the operation state of the switching HUB 2, and time synchronization of the switching HUB 2. Accuracy determination information indicating normality / abnormality is included.

  In addition, the electric quantity section includes electric quantity data of each phase, and the sub-communication section includes information such as the state of the protection relay 1. Here, the electrical quantity data of the electrical quantity unit includes information on the current I input to the input unit 3.

  Therefore, for example, the information of the current IA input to the input unit 3 of the protection relay 1A is transmitted to the protection relays 1B and 1C as sampling packet data after A / D conversion. On the other hand, the protection relay 1A receives the information of the currents IB and IC input to the input units 3 of the protection relays 1B and 1C as sampling packet data after A / D conversion.

≪Operation example≫
Hereinafter, an operation example of the protection relay system will be described. First, a system fault is detected by a difference current between currents sampled at the same time by the protection relays 1A to 1C provided at the terminals A to C of the transmission lines L1 to L3.

  Therefore, the sampling timing must be synchronized between the protection relays 1A to 1C. Here, the synchronization control of the sampling timing between the protection relays 1A to 1C is performed by the protection relays 1A to 1C receiving a signal of 1 PPS (one pulse per second) from the switching HUBs 2A to 2C, and the transmission / sampling synchronization control unit 5 Executed.

  For example, a clock signal having a clock frequency required by the CPU of the arithmetic unit 6 is generated from the 1PPS synchronous clock signal, and the sampling timing between the protection relays 1A to 1C is synchronized by using the clock signal synchronized with the generated 1PPS signal. be able to.

  At this time, according to the protection relay system, the sampling timing can be synchronized only by using the protection relays 1A to 1C and the switching HUBs 2A to 2C of the layer 2/3. A protection relay system using the device can be provided.

  Then, in the existing digital type current differential relay that mainly protects the transmission line, a dedicated device (master unit M / slave unit S) and an optical fiber cable are used for communication between the protection relays as in Patent Document 1. However, communication can be performed by constructing an IP network using a general-purpose communication device, and system introduction costs can be reduced. In this respect, the problem of the introduction cost as in Patent Document 2 of the system configuration based on the conventional communication using the dedicated line and the LAN communication can be solved.

  Next, sampling packet data is transmitted / received between the synchronous control units 5 of the protection relays 2 </ b> A to 2 </ b> C. However, in the following cases, since normal relay operation cannot be performed, erroneous tripping is prevented by relay lock.

(1) When the synchronization clock normal signal indicates an abnormality For example, when adjusting the time of the PTP, the adjustment amount (seconds) with the reference clock is recorded. A “maximum adjustment amount” is calculated based on the change in the recorded data, and the calculated “maximum adjustment amount” is used as the estimation accuracy. Whether the estimated accuracy is within the preset “target accuracy” is determined by the switching HUBs 2A to 2C. If the estimated accuracy is within the “target accuracy”, the synchronization clock signal is normal, but not within the “target accuracy”. Make the synchronous clock signal abnormal.

(2) When reference clock IDs included in each sampling packet data do not match Normally, a slave on the network performs time synchronization by referring to a reference clock of one master. However, when the network is divided into a plurality of times due to a network abnormality or the like, and then the network is restored again, the slave may temporarily refer to different masters at the time of the division as a reference clock. In this case, a state in which the reference clocks do not match occurs.

(3) When the accuracy determination information included in the sampling packet indicates a synchronization abnormality For example, when adjusting the PTP time, the time difference between the minimum round trip time of the PTP packet and the transmission time of the actual PTP packet round trip Based on this, a “measurement error” is calculated.

  If this "measurement error" is compared with "estimation accuracy" and the "measurement error" is not larger than "estimation accuracy", the measured value (round trip time) is used for time correction, and the accuracy judgment information is normal. Indicates. On the other hand, if the “current measurement error” is larger than the “estimated accuracy”, the measurement value (round trip time) is not used for time correction, and the accuracy determination information indicates a synchronization abnormality.

  In addition, this invention is not limited to the said embodiment, It can deform | transform and implement within the range described in each claim. For example, the protection relay system can be applied not only to a three-terminal power transmission system but also to a four-terminal power transmission system as in Patent Document 1.

1 ... Protective relay 2 ... Switching HUB (relay device)
5 ... Transmission / sampling synchronization controller A to C ... Terminal

Claims (5)

A protection relay system in which protection relays provided at each terminal of the power system are connected via a network via a time-synchronized relay device, and the amount of electricity in the system at each terminal is sampled by each protection relay to perform a relay calculation. There,
Each of the protection relays includes a transmission / sampling synchronization control unit that synchronously controls the sampling timing between the protection relays. The protection relay system according to claim 1, wherein the transmission / sampling synchronization control unit synchronizes the sampling timing based on a clock signal received from the relay device.   The protection relay system according to claim 1, wherein the relay device is time-synchronized according to the IEEE 1588 standard. Between each protection relay, send and receive sampling packet data including the electrical quantity data of the terminal provided with each protection relay via the relay device,
The protection relay system according to claim 1, wherein the relay calculation is executed based on an electric quantity included in the sampling packet data. The sampling packet data includes a reference clock ID that identifies the relay device having the reference clock for time synchronization, and accuracy determination information indicating normality / abnormality of time synchronization of the relay device,
The relay device further transmits a synchronization clock signal indicating whether time synchronization is within a target accuracy between the relay devices to the protection relay,
The protection relay includes a case where the synchronous clock signal is not within the target accuracy, a case where the reference clock ID included in each sampling packet data does not match, and a case where the accuracy determination information included in the sampling packet data is abnormal. The protection relay system according to claim 4, wherein relay lock is performed.

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