JP2016082458A - Sampling synchronization monitoring device for protective relay system, and sampling synchronization monitoring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To monitor and guarantee a synchronization performance of a sampling signal in a protective relay system.SOLUTION: A master device CL and slave devices SM1-SM4 which are provided in a plurality of terminals of a power system and temporally synchronized based on the IEEE1588 standard are connected over a LAN. The CL generates a sampling signal that is synchronized to a 1PPS signal of GPS and transmits a synchronization confirmation command to the SMs in timing of e.g., NO. 50 of the signal. Each of the SM1-SM4 generates a sampling signal in the same frequency as the master device side by an IEEE1588 temporal synchronization function, measures a difference between a signal change point time of the sampling signal of the present station that is first detected after the synchronization confirmation command is received, and a rise time of the 1PPS signal of GPS, and transmits the time difference information. A monitoring part of the CL that acquires the time difference information monitors the synchronization performance of the sampling signal on the basis of e.g., an appearance distribution situation of an oscillation width of the time difference from a minimum value to a maximum value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for monitoring sampling synchronization in a protection relay system.

  In recent years, IEEE 1588, which is a time synchronization protocol that can be used in Ethernet (registered trademark), has begun to be practically used in a system. IEEE 1588 can realize time synchronization with microsecond accuracy in Ethernet, which has been impossible until now, based on propagation delay time measurement data between nodes. As a result, it is possible to perform synchronization processing between a plurality of devices using Ethernet, which is widely used as a basic technology.

  In PCM current differential relays and system stabilization devices, in a protective relay device and system stabilization device that monitors and protects the amount of electricity over a wide area of the system, it is placed at different electrical locations. It is important to acquire the amount of electricity (current information, voltage information) at a timing synchronized between the devices with high accuracy.

  In the future, in Ethernet, which has been widely used to protect complicated power systems, the technology for obtaining the synchronized timing is a basic function.

  In the relay calculation, it is necessary to use sampling data of the amount of electricity (current information, voltage information) acquired at the same time, so the accuracy of sampling timing is an important factor.

  As the sampling timing signal, 50 Hz / 60 Hz, 12 times 600 Hz / 720 Hz, and 96 times 4.8 kHz / 5.76 kHz are mainly used. It is necessary to manage these timings with an error of about 20 microseconds.

  FIG. 11 shows an example of a digital relay system using the time synchronization function of IEEE 1588. In FIG. 11, master device CL (controller = IEEE 1588 synchronous master device) and a plurality of (four in this example) slave devices SM1 to SM4 (smart meter terminal = IEEE 1588 synchronous slave device) time-synchronized according to the IEEE 1588 standard. Are connected to each other via a LAN (or WAN).

  The master device CL and the slave devices SM1 to SM4 are arranged at the respective terminals of the power system. The slave devices SM1 to SM4 sample and capture analog inputs (electrical quantity information such as current and voltage) at each terminal by sampling signals generated by the local station in accordance with IEEE 1588 synchronization, digitally convert them, and master devices CL via the LAN. Send to. The master device CL performs a relay operation for detecting an accident in the power system based on the electrical quantity information of the power system transmitted from the slave devices SM1 to SM4.

  For example, a device described in Patent Document 1 has been proposed as a device that realizes highly accurate sampling synchronization by applying the IEEE 1588 technology to the protection relay system.

  The protection relay system described in Patent Document 1 is a method for managing packet transmission timing by time division within an electrical angle within a sampling period synchronized by IEEE 1588, and information is divided into a system current information packet by the plurality of packets. , And IEEE 1588 time management packet.

  The sampling synchronization method based on IEEE 1588 time synchronization is a new concept and is currently a protection relay when operating in a wide area (for example, when a synchronization system is constructed between devices located at a plurality of electric stations 200 km apart). No monitoring method has been established to guarantee the performance applied to the system.

JP 2011-200100 A

  IEEE 1588 time synchronization is a time synchronization function based on a PTP protocol (Precision Time Protocol) via a LAN, a WAN, or the like. This allows time synchronization with an accuracy of 1 microsecond, but when applied to an unknown number communication network, it is necessary to verify the influence of network delay. Also, monitoring that guarantees synchronization performance is necessary.

  IEEE 1588 time synchronization guarantees time synchronization but does not guarantee synchronization of a signal generated from the time synchronization function, for example, a sampling synchronization signal.

  For example, in the protection relay system including the master device CL and the four slave devices SM1 to SM4 in FIG. 11, a synchronization error occurs in the sampling signal generated by the IEEE1588 synchronization in each of the slave devices SM1 to SM4 as shown in FIG. .

  When a protection relay is configured by each of the slave devices SM1 to SM4, the phase of each sampling signal needs to be matched with an accuracy of about ± 20 μs. For this reason, when the difference between the sampling signal of the slave device SM2 and the sampling signal of the slave device SM3 is the maximum as shown in FIG. 12, this maximum error needs to be managed in 40 microseconds (± 20 μs). is there.

  The present invention solves the above-described problems, and an object of the present invention is to provide a sampling synchronization monitoring apparatus and method for a protection relay system that can monitor and guarantee the synchronization performance of each sampling signal.

  A sampling synchronization monitoring device of a protection relay system according to claim 1 for solving the above-mentioned problem is provided at a plurality of terminals of an electric power system, and a master device and a plurality of slave devices time-synchronized according to the IEEE 1588 standard are connected to a network. In the protection relay system that performs relay calculation by sampling the electrical quantity information of the system at each terminal by each device, the master device is a master having a predetermined frequency synchronized with the 1PPS signal acquired from the GPS receiver. Means for generating a device-side sampling signal, and means for transmitting a synchronization confirmation command to a plurality of slave devices via the network at a timing set in the master device-side sampling signal, wherein each slave device has an IEEE 1588 time The synchronization function A means for generating a slave device side sampling signal having the same frequency as the star device side sampling signal, a signal change point time of the slave device side sampling signal detected after receiving the synchronization confirmation command from the master device, and a reference at a predetermined cycle A time difference measuring unit that measures a difference from a reference signal generation time of a reference signal source that emits a signal as a time difference of a synchronization signal; and a unit that transmits time difference information of the measured synchronization signal to the network. , Provided in at least one of a plurality of slave devices and a monitoring terminal device provided on the network, acquiring time difference information of a synchronization signal transmitted from each of the slave devices via the network, and acquiring the time difference Based on the information, the master device side sampling signal and the slave device It is characterized in that a monitoring means for monitoring the synchronization performance of the sampling signal.

  The sampling synchronization monitoring method of the protection relay system according to claim 8 is provided at a plurality of terminals of the power system, and a master device and a plurality of slave devices time-synchronized according to the IEEE 1588 standard are connected via a network, A sampling synchronization monitoring method for a protection relay system that performs relay calculation by sampling electrical quantity information of a system at each terminal by each device, wherein the master device synchronizes with a 1 PPS signal acquired from a GPS receiver. Generating a master device side sampling signal, a step in which the master device transmits a synchronization confirmation command to a plurality of slave devices via the network at a timing set in the master device side sampling signal, and each slave The device is IEEE A step of generating a slave device side sampling signal having the same frequency as the master device side sampling signal by the 588 time synchronization function, and a time difference measuring means of each slave device detects after receiving a synchronization confirmation command from the master device; A time difference measuring step of measuring a difference between a signal change point time of a sampling signal on a slave device side and a reference signal generation time of a reference signal source that emits a reference signal at a predetermined period as a time difference of a synchronization signal; and each of the slave devices, Monitoring means provided in at least one of the step of transmitting the time difference information of the measured synchronization signal to the network, and the master device, the plurality of slave devices, and the monitoring terminal device provided on the network; Sent from each slave device via a network. Acquires time difference information of the synchronization signals, based on said time difference information, it is characterized by comprising a monitoring step of monitoring the synchronization performance of the master device side sampling signal and the slave device side sampling signal.

  According to the above configuration, since the time difference between the master device side sampling signal and the slave device side sampling signal is measured based on the reference signal generation time, the master device side sampling signal and the slave device side sampling are determined based on the measured time difference information. Signal synchronization performance can be monitored.

  Thus, for example, by confirming that the time difference is within a threshold value, it is possible to guarantee the synchronization performance, that is, the validity of the relay synchronization signal.

  Further, the sampling synchronization monitoring device of the protection relay system according to claim 2 is the sampling synchronization monitoring device according to claim 1, wherein each of the slave devices transmits time difference information of the measured synchronization signal to all devices connected to the network. It has a feature of transmitting and receiving between.

  Further, the sampling synchronization monitoring method of the protection relay system according to claim 9 is the monitoring synchronization monitoring method according to claim 8, wherein each of the slave devices transmits the time difference information of the measured synchronization signal to all the devices connected to the network. It is characterized by having a step of transmitting and receiving between.

  According to the above configuration, it is possible to grasp the state of synchronization on the same network by exchanging information on the time difference of the synchronization signals of each of the plurality of slave devices. For this reason, for example, when the time difference is equal to or greater than the threshold, that is, when the sampling error is equal to or greater than the threshold, the output of the slave device side sampling signal is controlled to reduce the sampling error, thereby improving the relay performance. it can.

  According to a third aspect of the present invention, there is provided the sampling synchronization monitoring device for a protection relay system according to the first or second aspect, wherein the reference signal generated at the predetermined period is a 1PPS signal acquired from a GPS receiver, and the time difference measuring means is The time difference between the signal change point time of the slave device side sampling signal detected after receiving the synchronization confirmation command from the master device and the 1PPS signal generation time is measured.

  Further, the sampling synchronization monitoring method for the protection relay system according to claim 10 is the slave device side sampling signal according to claim 8 or 9, wherein the time difference measurement step is detected after receiving a synchronization confirmation command from the master device. The time difference between the signal change point time and the 1PPS signal generation time acquired from the GPS receiver is measured.

  According to the above configuration, the time difference between the sampling signal on the master device side and the sampling signal on the slave device side is measured based on the GPS 1PPS signal (pulse signal at 1-second intervals) that is the absolute time. The synchronization performance monitoring reliability is improved.

  According to a fourth aspect of the present invention, there is provided the sampling synchronization monitoring device for the protection relay system according to the first or second aspect, wherein the reference signal generated at the predetermined period is a signal detecting a power system frequency, and the time difference measuring means is A time difference between a signal change point time of a slave device side sampling signal detected after receiving a synchronization confirmation command from the master device and a zero cross point of the detected power system frequency signal is measured.

  Further, the sampling synchronization monitoring method of the protection relay system according to claim 11 is the slave device side sampling signal according to claim 8 or 9, wherein the time difference measurement step is detected after receiving a synchronization confirmation command from the master device. The time difference between the signal change point time and the zero cross point of the signal from which the power system frequency is detected is measured.

  According to the above configuration, since the GPS receiver is not used, construction of the GPS receiver and the GPS antenna becomes unnecessary.

  According to a fifth aspect of the present invention, there is provided the sampling synchronization monitoring device for a protection relay system according to any one of the first to fourth aspects, wherein the monitoring means is configured to measure from a minimum value of a measurement time difference indicated by time difference information of the synchronization signal to a maximum value. The processing for obtaining the width up to the value as the fluctuation width is executed for the time difference information of the plurality of synchronization signals acquired within the monitoring target time, and the synchronization is performed based on the appearance distribution status of the plurality of fluctuation widths obtained as a result. It is characterized by monitoring performance.

  According to a twelfth aspect of the present invention, there is provided the sampling synchronization monitoring method for the protection relay system according to any one of the eighth to eleventh aspects, wherein the monitoring step is performed from the minimum value of the measurement time difference indicated by the time difference information of the synchronization signal to the maximum value. The processing for obtaining the width up to the value as the fluctuation width is executed for the time difference information of the plurality of synchronization signals acquired within the monitoring target time, and the synchronization is performed based on the appearance distribution status of the plurality of fluctuation widths obtained as a result. It is characterized by monitoring performance.

  Since the slave device is dependently synchronized with the master device, the time difference of the synchronization signal has fluctuation characteristics. According to the configurations of the fifth and twelfth aspects, the synchronization performance can be monitored according to the fluctuation characteristics. .

  According to a sixth aspect of the present invention, there is provided the sampling synchronous monitoring device for a protection relay system according to the fifth aspect, wherein the monitoring means classifies the obtained fluctuation width into a plurality of appearance rates set in stages. Thus, the synchronization performance is monitored.

  Moreover, the sampling synchronous monitoring method of the protection relay system according to claim 13, according to claim 12, wherein the monitoring step classifies the obtained fluctuation width into a plurality of appearance rates set in stages. Thus, the synchronization performance is monitored.

  According to the above configuration, it is possible to evaluate a stepwise fluctuation situation with respect to the fluctuation of the time difference of the synchronization signal.

  Further, a sampling synchronization monitoring device for a protection relay system according to claim 7 is the sampling synchronization monitoring device according to any one of claims 1 to 6, wherein the monitoring means includes means for displaying information for monitoring the synchronization performance. It is characterized by having.

  Further, according to a sampling synchronization monitoring method for a protection relay system according to claim 14, in any one of claims 8 to 13, the monitoring step displays information for the display means to monitor the synchronization performance. It is characterized by having steps.

  According to the above configuration, the information for monitoring the synchronization performance, for example, the time difference information between the master device side sampling signal and the slave device side sampling signal, the time difference fluctuation width information, the fluctuation width appearance distribution status information, and the fluctuation width. Information classified for each of a plurality of appearance rates set in stages can be displayed. Since the information for monitoring the synchronization performance is visualized in this way, it is possible to evaluate the level of network stability and quality.

(1) According to the invention described in claims 1 to 14, it is possible to monitor the synchronization performance of the master device side sampling signal and the slave device side sampling signal. As a result, the synchronization performance of the sampling synchronization signal can be guaranteed based on the monitoring result.
(2) According to the second and ninth aspects of the invention, the time difference information of the synchronization signals of the plurality of slave devices can be shared with each other, and the synchronization status on the same network can be grasped.
(3) According to the invention described in claims 3 and 10, the accuracy of the time difference information of the measured synchronization signal is high, and the reliability of the synchronization performance monitoring is improved.
(4) According to the inventions described in claims 4 and 11, since a GPS receiver is not used, an inexpensive apparatus configuration is obtained.
(5) According to the inventions described in claims 5 and 12, the synchronization performance can be monitored according to the fluctuation characteristics of the time difference of the synchronization signal.
(6) According to the inventions described in claims 6 and 13, it is possible to evaluate the state of the stepwise fluctuation with respect to the fluctuation of the time difference of the synchronization signal.
(7) According to the inventions described in claims 7 and 14, information for monitoring the synchronization performance can be displayed and visualized, thereby enabling evaluation of network stability and quality level. .

The block diagram of the synchronous monitoring system by Example 1 of this invention. Explanatory drawing which shows the time difference measurement of the synchronizing signal in Example 1 of this invention. The block diagram of the synchronous monitoring system by Example 2 of this invention. Explanatory drawing which shows the state of the time difference measurement of the synchronizing signal in Example 2 of this invention. Explanatory drawing which shows the example of a time difference measurement of the synchronizing signal in Example 2 of this invention. The characteristic view which shows distribution of fluctuation width (DELTA) tn of the time difference of the synchronizing signal used by this invention. The block diagram of the synchronous monitoring system by Example 3 of this invention. Explanatory drawing which shows the example of a sampling error monitoring screen on the network in Example 3 of this invention. Explanatory drawing which shows the example of fluctuation distribution display of the sampling error monitoring screen on the network in Example 4 of this invention. The characteristic view which shows distribution of fluctuation width (DELTA) tn of the time difference of the synchronizing signal used in Example 4 of this invention. The block diagram which shows an example of the conventional digital relay system which uses the time synchronous function of IEEE1588. Explanatory drawing which shows the synchronization error of the sampling signal of each slave apparatus in the system of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. The basic configuration of the protection relay system of this embodiment is configured as shown in FIG. 1 (Example 1), for example.

  In FIG. 1, master device CL (controller = IEEE 1588-synchronized master device) and a plurality of (four in this example) slave devices SM1 to SM4 (smart meter terminal = IEEE 1588-synchronized slave device), time-synchronized according to the IEEE 1588 standard. Are connected to each other via a LAN (or WAN) (the network of the present invention).

  The master device CL and the slave devices SM1 to SM4 are arranged at the respective terminals of the power system. The slave devices SM1 to SM4 sample and capture analog inputs (electrical quantity information such as current and voltage) at each terminal by sampling signals generated by the local station in accordance with IEEE 1588 synchronization, digitally convert them, and master devices CL via the LAN. Send to. The master device CL performs a relay operation for detecting an accident in the power system based on the electrical quantity information of the power system transmitted from the slave devices SM1 to SM4.

For example, the slave devices SM1 to SM4 detect the current at each terminal by the current transformer CT provided at each terminal of the system, take in the contact information of the circuit breaker provided at each terminal, and detect the detected current information and contact information. Is transmitted to the master device CL via the LAN.
The master device CL performs a relay operation using the detected current information, contact information, and the like, and gives a trip command to the breaker of each terminal based on the result. The master device CL is a sampling signal generator for generating a master device side sampling signal having a predetermined frequency synchronized with the 1PPS signal acquired from the GPS receiver, and sends a synchronization confirmation command to the LAN at a timing set in the master device side sampling signal. A transmission unit that transmits data to a plurality of slave devices SM1 to SM4, an A / D conversion unit, a reception unit that receives various types of information, a display unit that displays various types of information, a CPU that performs various arithmetic processes, and the like.
Each of the slave devices SM1 to SM4 receives a synchronization confirmation command from the master device CL, a sampling signal generation unit that generates a slave device side sampling signal having the same frequency as the master device side sampling signal by the IEEE 1588 time synchronization function. Time difference measuring unit that measures the difference between the signal change point time of the detected sampling signal on the slave device side and the reference signal source that emits the reference signal at a predetermined period, for example, the 1PPS signal generation time acquired from the GPS receiver, as the time difference of the synchronization signal A transmission unit that transmits time difference information of the measured synchronization signal to the LAN, an A / D conversion unit, a reception unit that receives various information, a display unit that displays various information, a CPU that performs various arithmetic processes, and the like ing.

Furthermore, at least one of the master device CL, the plurality of slave devices SM1 to SM4 and the monitoring terminal device (not shown) provided on the LAN is connected to the slave devices SM1 to SM4 via the LAN. A monitoring unit is provided for acquiring time difference information of the transmitted synchronization signals and monitoring the synchronization performance of the master device side sampling signal and the slave device side sampling signal based on the time difference information.
In the description of this embodiment, the 50 Hz signal is defined as sync4 on behalf of 50 Hz, and the 600 Hz signal, which is a multiplication of 12 times, is defined as sync1.

  In the case of the 60 Hz system, a 60 Hz signal is defined as sync4, and a 720 Hz signal, which is a multiplication of 12 times, is defined as sync1. The actual sampling frequency is 96 times 4.8 KHz or 5.76 KHz.

  In the first embodiment, the time difference between the 1PPS signal from the GPS receiver and the sampling synchronization signal is measured in FIG. 1, and the appearance rate of the time difference is monitored to ensure the synchronization performance. That is, as shown in FIG. 2, the 1PPS signal (pulse signal at 1 second intervals) received from the GPS receiver is taken into the master device CL, and the time difference from the change point of the sampling synchronization signal is measured at that timing.

  The sampling signal includes a 50 Hz signal (sync4) and a 600 Hz signal (sync1), but the 50 Hz signal (sync4) is used to determine the establishment of synchronization with other devices.

  (1) The sampling signal generator of the master device CL generates a sampling synchronization signal (master device-side sampling signal) in synchronization with the 1PPS signal from the GPS receiver ((1) in FIG. 1).

  (2) Since the 1PPS signal is 1 second time, there is a sampling signal sync4 (50 Hz) having 50 changing points in the period of the next 1PPS signal, and the interval time of each changing point is set to NO. 1 to NO. 50 ((2) in FIG. 1).

  (3) Section NO. The change point of one sampling signal sync4 will be described as the rising change point of the 1PPS signal, and the falling point of the sampling signal sync4 will be described as the same time point ((3) in FIG. 1).

  Since the master device CL and the slave devices SM connected to a plurality of networks (LANs) by the IEEE 1588 PTP protocol have the same CL → SM □ transmission delay and SM □ → CL transmission delay, synchronization is established. (□ is the slave device number). The synchronization is performed by using CL as a master and each SM □ as a slave.

  (4) From the master device CL to the slave device SM □, NO. At the fall timing of 50, a PTP protocol packet for synchronization confirmation (synchronization confirmation command) is transmitted ((4) in FIG. 1).

  (5) The slave device SM □ has time synchronization established with the master device CL by the IEEE 1588 time synchronization function (PTP). Each slave device SM □ generates a sampling synchronization signal sync4 (slave device-side sampling signal; (5) in FIG. 1) from the time synchronization function (a sync1 obtained by multiplying the sync4 is also generated).

  (6) The 1PPS signal from the GPS receiver is also captured in the slave devices SM1 to SM4 ((6) in FIG. 1).

  (7) When the time difference measuring unit of the slave device SM □ recognizes the synchronization confirmation data (the timing of sync4 of NO. 50), the signal of the sampling signal (sync4) of the own station that is detected first from the recognized timing The time difference between the change point (the beginning of sync No. 1) and the 1PPS signal is measured ((7) in FIG. 2; time differences t1 to t4).

  Then, the slave devices SM1 to SM4 transmit the time differences t1 to t4 (synchronous signal time difference information) measured by the local station via the LAN.

In FIG.
SM1 sampling signal sync4 NO. 1 falling point time is GPS 1PPS signal + t1,
SM2 sampling signal sync4 NO. 1 falling point time is GPS 1PPS signal + t2,
SM3 sampling signal sync4 NO. 1 falling point time is GPS 1PPS signal + t3,
SM4 sampling signal sync4 NO. The time at the falling point of 1 is the GPS 1PPS signal + t4.

  Although omitted in FIG. 2, the same applies to the master device CL. Sampling signal sync4 NO. The falling time of 1 is GPS 1PPS signal + t0.

  Accordingly, the maximum value of the change width of the sampling signal sync4 at the time point n (NO. 1 to NO. 50) is the minimum (t1, t2, t3, t4) tn (min), and the maximum (t1, t4). Let t2, t3, t4) be tn (max). The fluctuation width to be managed is Δtn = tn (max) −tn (min) ≦ 40 μs. Since the synchronization timing circuit on the slave device SM side is dependently synchronized using a digital PLL system or the like, the time difference (t1, t2, t3, t4) fluctuates.

  The present invention is characterized in that the fluctuation width Δtn is managed by monitoring. In the first embodiment and the second embodiment, as an example, a monitoring unit is provided on the master device CL side, and the monitoring unit acquires and monitors time difference information (t1 to t4) transmitted from the slave devices SM1 to SM4. The fluctuation width Δtn is obtained from a plurality of time difference information acquired within the target time, and the synchronization performance of the master device side sampling signal and the slave device side sampling signal is monitored based on the appearance distribution state of the plurality of fluctuation widths Δtn.

  The Δtn can prepare 50 evaluation data in one second. For example, the occurrence frequency of Δtn is evaluated with 50 of them. For example, if the number of data samples is 10 seconds, 50 × 10 seconds = 500 pieces of statistical data. The distribution state of fluctuation of Δtn is distributed in a normal distribution as shown in FIG. As monitoring, the statistical target time tm (for example, 10 seconds), the center value M, and 3σ are obtained. This 3σ is monitored such that the control point is ± 20 μs or less.

  (8) As described above, since the measured time difference is constant, it can be ensured that the synchronization of the sampling synchronization signal is established between the master device CL and the slave devices SM1 to SM4.

  That is, it is possible to measure the time difference from the sampling signal generated on each slave device SM1 to SM4 using the GPS 1PPS signal as a reference, and check the synchronization by checking whether the time difference is constant or not. Furthermore, when the time difference is within ± 20 μs, it can be ensured that the relay synchronization signal is valid.

  In the configuration of FIG. 3, the power system frequency is used as a reference in the configuration of FIG. 3, the time difference with the sampling synchronization signal is measured, and the appearance rate of the time difference is monitored to ensure the synchronization performance.

  That is, as shown in FIG. 4, the zero cross point of the signal whose power system frequency (for example, current phase) is detected is taken into the apparatus, and the time difference from the change point of the sampling synchronization signal is measured at that timing.

  The sampling signal includes a 50 Hz signal (sync4) and a 600 Hz signal (sync1), but the 50 Hz signal (sync4) is used to determine the establishment of synchronization with other devices.

  3, the same parts as those in FIG. 1 are denoted by the same reference numerals. The difference from FIG. 1 is that the time difference measuring unit of each of the slave devices SM1 to SM4 performs zero crossing of the power system analog input (a signal that detects the power system frequency). Point and measuring the time difference between the signal change point time of the slave device side sampling signal detected first after receiving the synchronization confirmation command from the master device CL, and other parts are the same as in FIG. ing.

  (1) The sampling signal generator of the master device CL generates a sampling synchronization signal (master device side sampling signal) in synchronization with the 1PPS signal from the GPS receiver ((1) in FIG. 3).

  (2) Since the 1PPS signal is 1 second time, there is a sampling signal sync4 (50 Hz) having 50 changing points in the period of the next 1PPS signal, and the interval time of each changing point is set to NO. 1 to NO. 50 ((2) in FIG. 3).

  (3) Section NO. The change point of one sampling signal sync4 will be described as the rising change point of the 1PPS signal, and will be described as the same time point as the falling point of the sampling signal sync4 ((3) in FIG. 3).

  (4) From the master device CL to the slave device SM □, NO. At the fall timing of 50, a PTP protocol packet for synchronization confirmation (synchronization confirmation command) is transmitted ((4) in FIG. 3).

  (5) The slave device SM □ has time synchronization established with the master device CL by the IEEE 1588 time synchronization function (PTP). Each slave device SM □ generates a sampling synchronization signal sync4 (slave device side sampling signal; (5) in FIG. 3) from the time synchronization function (a sync1 obtained by multiplying the sync4 is also generated).

  (6) The slave devices SM1 to SM4 are provided with a circuit for detecting a zero cross point of the power system frequency from the analog input signal ((6) in FIG. 3).

  (7) When the time difference measuring unit of the slave device SM □ recognizes the synchronization confirmation data (the timing of sync4 of NO. 50), the signal of the sampling signal (sync4) of the own station that is detected first from the recognized timing The time difference between the change point (the head of sync No. 1) and the zero cross point of the power system frequency is measured ((7) in FIG. 4; time differences t1 to t4).

  Then, the slave devices SM1 to SM4 transmit the time differences t1 to t4 (synchronous signal time difference information) measured by the local station via the LAN.

The time difference (t1 to t4) is the NO. Of the sampling signal of each station of the slave device SM. The time T □ from the time point 1 falls to the zero cross point of the power system is calculated for each slave device SM □, and the time difference t □ is calculated from one cycle of the power system analog input as shown in FIG. It is obtained by subtracting the time T □. That is,
SM1 sampling signal sync4 NO. The time of the falling point of 1 is t1 = 1 period T: 20 ms-T1,
SM2 sampling signal sync4 NO. The time of the falling point of 1 is t2 = 1 period T: 20 ms-T2,
SM3 sampling signal sync4 NO. The time of the falling point of 1 is t3 = 1 period T: 20 ms-T3,
SM4 sampling signal sync4 NO. The time of the falling point of 1 is t4 = 1 period T: 20 ms−T4.

  Although omitted in FIG. 4, the same applies to the master device CL. Sampling signal sync4 NO. The falling time of 1 is GPS 1PPS signal + t0.

  Therefore, the maximum value of the change width of the sampling signal sync4 at time n is tn (min) for the minimum (t1, t2, t3, t4) and tn (max) for the maximum (t1, t2, t3, t4). The fluctuation width to be managed is Δtn = tn (max) −tn (min) ≦ 40 μs. Since the synchronization timing circuit on the slave device SM side is dependently synchronized using a digital PLL system or the like, the time difference (t1, t2, t3, t4) fluctuates.

  In the second embodiment, the monitoring unit provided on the master device CL side acquires the time difference information (t1 to t4) transmitted from the slave devices SM1 to SM4, and the plurality of time difference information acquired within the monitoring target time. The fluctuation width Δtn is obtained, and the synchronization performance of the sampling signal on the master device side and the sampling signal on the slave device side is monitored based on the appearance distribution state of the plurality of fluctuation widths Δtn.

  For example, 50 evaluation data can be prepared for Δtn per second (because the power system analog input is 50 Hz as shown in the time difference measurement example of FIG. 5), and the fluctuation width Δtn is generated with 50 of them. Assess frequency. For example, if the number of data samples is 10 seconds, 50 × 10 seconds = 500 pieces of statistical data. The distribution state of fluctuation of Δtn is distributed in a normal distribution as shown in FIG. As monitoring, the statistical target time tm (for example, 10 seconds), the center value M, and 3σ are obtained. This 3σ is monitored such that the control point is ± 20 μs or less.

  (8) As described above, since the measured time difference is constant, it can be ensured that the synchronization of the sampling synchronization signal is established between the master device CL and the slave devices SM1 to SM4.

  That is, the time difference from the sampling signal generated on each slave device SM1 to SM4 side is measured with reference to the signal that detects the power system frequency (for example, current phase), and whether or not the time difference is constant in the monitoring unit. Thus, the synchronization can be confirmed, and the time difference is within ± 20 μs, so that it can be ensured that the signal is valid as a relay synchronization signal.

  In the third embodiment, in FIG. 7, the sampling time synchronization information (time difference information) is shared by all the devices, and an error from the sampling timing of the own device is managed (sampling synchronization accuracy management).

  That is, the time difference information measured in the first and second embodiments (1PPS signal from the GPS that is the reference signal, or the time difference information between the zero cross point of the system current phase and the sampling synchronization signal of the own station) is used for all devices. (CL, SM) are shared via the LAN. As a result, it is possible to grasp at what time the fixed-cycle signal is managed between devices that are equipped with the IEEE 1588 function at a remote location.

  The synchronization monitoring system in FIG. 7 is configured in the same manner as in FIGS. 1 and 3. The difference from FIGS. 1 and 3 is that each slave device SM1 to SM4 uses the time difference information of the synchronization signal measured at its own station. And having a function of transmitting and receiving data to and from all devices on the LAN.

  In FIG. 7, the monitoring means (monitoring unit) of the present invention is any of the master device CL, the slave devices SM1 to SM4, and the monitoring device (personal computer) (not shown) for the synchronous monitoring system provided on the LAN. Or more than one.

  In the system of FIG. 7, if the information between the five terminals (CL, SM1 to SM4) is collected, the sampling synchronization status of all devices can be monitored. Monitoring points (synchronous monitoring systems) on the network (personal computers) or information sharing terminals manage the changing points of sampling signals, which are fixed timings, using absolute time information. Thus, visual display is possible on the display unit of the monitoring unit. As an example, FIG. 8 shows an example of a sampling error monitoring screen on the monitoring device (personal computer) for the synchronous monitoring system.

  If there is a monitoring device (personal computer) for the synchronous monitoring system that manages absolute time with GPS, for example, the time difference (fluctuation width min-max) based on it can be displayed and managed as shown in FIG. It is. By continuous monitoring, for example, it is expressed as fluctuation widths O to O using 500 data for 10 seconds (when measured at a cycle of 50 Hz). The update cycle is, for example, updated every second.

  In addition, the value shown in the measured value of FIG. 8 is an example. As a relay, the synchronization accuracy within ± 20 μsec is essential, so the resolution is displayed at least 1 μsec. As the fluctuation display, IEEE 1588 can display the time on the nsec level, so the resolution display is 0.1 μsec.

  In this way, it is possible to monitor the synchronization performance of all the devices on the LAN. In addition, the abnormality determination is a mechanism that does not cause a loss of synchronization immediately even if time correction cannot be performed at the time of communication failure based on the mechanism of IEEE 1588. For that purpose, for example, a control point ± 20 ms is deviated and a warning is issued in 10 seconds.

  Further, the relay performance can be improved by controlling the output of the sampling signal of the own device (any one of the slave devices SM1 to SM4) so that the measured sampling decreases the difference.

  In the sampling synchronization accuracy management realized in the third embodiment, fluctuations (min to max) are evaluated, but in the fourth embodiment, the level of network stability and quality can be evaluated by more visualizing the fluctuation state. A possible mechanism was built.

  In the fourth embodiment, as in the configuration of FIG. 7 of the third embodiment, the time difference information of the synchronization signal is shared by all the devices (CL, each SM), and the monitoring unit aggregates all the time difference information and collects the time difference. The fluctuation width (min to max) is the same, but the fluctuation width is further classified into a plurality of appearance rates set in stages to perform display management.

  For example, by continuous monitoring, fluctuation widths O to O using 500 data for 10 seconds (when measured at a cycle of 50 Hz) are expressed for each appearance rate as shown in FIG. The update cycle is, for example, updated every second. The distribution of the fluctuation width Δtn is as shown in FIG.

  FIG. 9 shows an example of a sampling error monitoring screen displayed by the display unit of the monitoring unit. In FIG. 9, time variation of Δtn with an appearance rate of ± 30%, time variation of Δtn with an appearance rate of ± σ (69%), and time variation of Δtn with an appearance rate of ± 3σ (99.6%) Are represented by black, hatched, and white bands, ± 30% is black, ± σ (69%) is shaded, and ± 3σ (99.6%) is white. .

  In addition, the value shown in the measured value of FIG. 9 is an example. As a relay, the synchronization accuracy within ± 20 μsec is essential, so the resolution is displayed at least 1 μsec. As the fluctuation display, IEEE 1588 can display the time on the nsec level, so the resolution display is 0.1 μsec.

  According to the fourth embodiment, the fluctuation width of the time difference information is classified for each of a plurality of appearance rates set in stages, and the fluctuation performance in stages can be evaluated by visualizing the fluctuation situation. Network stability and quality level can be evaluated.

CL ... Master device SM1-SM4 ... Slave device GPS ... GPS receiver

Claims (14)

A master device and a plurality of slave devices, which are provided at a plurality of terminals of the power system and are time-synchronized according to the IEEE 1588 standard, are connected via a network. In the protection relay system that performs
The master device generates a master device side sampling signal having a predetermined frequency synchronized with the 1PPS signal acquired from the GPS receiver, and a synchronization confirmation command at a set timing in the master device side sampling signal via the network. Means for transmitting to a plurality of slave devices,
Each slave unit generates means for generating a slave unit side sampling signal having the same frequency as the master unit side sampling signal by the IEEE 1588 time synchronization function, and slave unit side sampling detected after receiving a synchronization confirmation command from the master unit A time difference measuring means for measuring a difference between a signal change point time of a signal and a reference signal generation time of a reference signal source that emits a reference signal at a predetermined cycle as a time difference of the synchronization signal; and time difference information of the measured synchronization signal Means for transmitting to the network,
Provided in at least one of the master device, a plurality of slave devices, and a monitoring terminal device provided on a network, and acquires time difference information of a synchronization signal transmitted from each slave device via a network. A sampling synchronization monitoring device for a protection relay system, comprising monitoring means for monitoring the synchronization performance of the master device side sampling signal and the slave device side sampling signal based on the time difference information.   The said each slave apparatus has a function which transmits and receives the time difference information of the measured synchronous signal between all the apparatuses connected to the said network. Sampling synchronous monitoring device for protection relay system. The reference signal emitted at the predetermined cycle is a 1PPS signal acquired from a GPS receiver,
The time difference measuring means measures a time difference between a signal change point time of a slave device side sampling signal detected after receiving a synchronization confirmation command from the master device and the 1PPS signal generation time. The sampling synchronous monitoring apparatus of the protection relay system of 1 or 2. The reference signal generated in the predetermined cycle is a signal that detects the power system frequency,
The time difference measuring means measures a time difference between a signal change point time of a sampling signal on the slave device side detected after receiving a synchronization confirmation command from the master device and a zero cross point of the detected power system frequency signal. The sampling synchronous monitoring apparatus of the protection relay system according to claim 1 or 2.   The monitoring means executes processing for obtaining a width from a minimum value to a maximum value of a measurement time difference indicated by the time difference information of the synchronization signal as a fluctuation width with respect to time difference information of a plurality of synchronization signals acquired within the monitoring target time. The sampling synchronization monitoring device for a protection relay system according to any one of claims 1 to 4, wherein the synchronization performance is monitored based on an appearance distribution state of a plurality of fluctuation widths obtained as a result thereof. .   6. The protection relay system according to claim 5, wherein the monitoring unit monitors the synchronization performance by classifying the obtained fluctuation width into a plurality of appearance rates set in stages. Sampling synchronization monitoring device.   The sampling synchronization monitoring apparatus for a protection relay system according to any one of claims 1 to 6, wherein the monitoring means includes means for displaying information for monitoring the synchronization performance. A master device and a plurality of slave devices, which are provided at a plurality of terminals of the power system and are time-synchronized according to the IEEE 1588 standard, are connected via a network. A sampling synchronous monitoring method for a protection relay system that performs
The master device generating a master device side sampling signal having a predetermined frequency synchronized with the 1PPS signal acquired from the GPS receiver;
The master device transmits a synchronization confirmation command to the plurality of slave devices via the network at a set timing in the master device-side sampling signal;
Each of the slave devices generates a slave device side sampling signal having the same frequency as the master device side sampling signal by the IEEE 1588 time synchronization function;
The time difference measuring means of each slave device detects the signal change point time of the slave device side sampling signal detected after receiving the synchronization confirmation command from the master device, and the reference signal generation of the reference signal source that emits the reference signal at a predetermined cycle A time difference measuring step for measuring a difference from the time as a time difference of the synchronization signal;
Each slave device transmits the time difference information of the measured synchronization signal to the network;
The time difference between the synchronization signals transmitted from each slave device via the network by the monitoring means provided in at least one of the master device, the plurality of slave devices, and the monitoring terminal device provided on the network. Monitoring step of acquiring information and monitoring the synchronization performance of the sampling signal on the master device side and the sampling signal on the slave device side based on the time difference information;
A sampling synchronization monitoring method for a protection relay system, comprising:   9. The method according to claim 8, wherein each of the slave devices has a step of transmitting and receiving the time difference information of the measured synchronization signal to and from all devices connected to the network. Sampling synchronous monitoring method for protection relay system.   The time difference measuring step measures the time difference between the signal change point time of the slave device side sampling signal detected after receiving the synchronization confirmation command from the master device and the 1PPS signal generation time acquired from the GPS receiver. 10. The sampling synchronization monitoring method for a protection relay system according to claim 8 or 9, characterized in that:   The time difference measuring step measures the time difference between the signal change point time of the sampling signal on the slave device side detected after receiving the synchronization confirmation command from the master device and the zero cross point of the signal detecting the power system frequency. 10. The sampling synchronization monitoring method for a protection relay system according to claim 8 or 9, characterized in that:   The monitoring step executes a process for obtaining a width from a minimum value to a maximum value of a measurement time difference indicated by the time difference information of the synchronization signal as a fluctuation width with respect to time difference information of a plurality of synchronization signals acquired within the monitoring target time. The sampling synchronization monitoring method for a protection relay system according to any one of claims 8 to 11, wherein the synchronization performance is monitored based on an appearance distribution situation of a plurality of fluctuation widths obtained as a result. .   13. The protection relay system according to claim 12, wherein the monitoring step monitors the synchronization performance by classifying the obtained fluctuation width into a plurality of appearance rates set in stages. Sampling synchronous monitoring method.   The sampling synchronization monitoring of the protection relay system according to any one of claims 8 to 13, wherein the monitoring step comprises a step of displaying information for the display means to monitor the synchronization performance. Method.

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