JP5501909B2 - Protection relay - Google Patents

Description

  The present invention relates to a protection relay that takes in a system electricity amount from a power system and converts analog data related to the system electricity amount into digital data to protect the power system.

  A general protection relay (hereinafter referred to as “conventional protection relay”) is installed in the vicinity of a transmission line, takes in a current or voltage from an electric power system (hereinafter referred to as “system electricity”) into a relay unit, and then relays. An internal input transformer converts the grid electricity to a size that is easy for the relay to handle, converts analog data to digital data (AD conversion), and performs relay calculations such as accident detection based on the AD conversion data. Output to. Thus, the conventional protection relay performs these series of processes in the same unit.

  On the other hand, what divided | segmented the function of the protection relay into two functions mainly is called a process bus corresponding | compatible protection relay. Specifically, the process bus compatible protection relay is installed in the vicinity of a main circuit such as a circuit breaker or an instrument transformer (CT / VT). It consists of a unit called an IED (intelligent electric device) that is installed in a remote place (for example, a control room) and performs a relay operation. Here, the instrument transformer (CT / VT) is a general term for a current transformer (CT) and a voltage transformer (VT). The MU and the IED are connected by a process bus (LAN or a dedicated serial bus). The MU performs analog-to-digital conversion of analog data from the power system using an input transformer, and converts the converted data or data obtained by performing gain adjustment, phase correction, or other processing on the process bus as AI (Analog Input) data. To the IED. The IED performs relay calculations such as accident detection based on AI data from the MU. The AI data is data after processing such as gain and phase correction, and is transmitted to the IED.

  On the other hand, a protection relay that exchanges AD-converted data through PCM communication is called a so-called PCM relay (Pulse Code Modulation relay), and two or more protection relays transmit AI data to each other. By comparing the two, the transmission line accident is detected and protected. However, the PCM relay needs to sample the grid electricity quantity at the same timing in order to ensure simultaneity with other protection relays. Therefore, in the PCM relay, it is necessary to synchronize AD conversion timing among a plurality of relays. Even when the timing of AD conversion cannot be synchronized, AI data to be compared between a plurality of relays needs to have substantially the same timing by phase correction or the like.

  For example, the conventional protection relay disclosed in Patent Document 1 includes a unit that performs analog-to-digital conversion of analog data from the power system, and a unit that performs PCM communication (transmission and reception of AD conversion data between the protection relays) with other protection relays. Since the unit that performs the PCM communication can control the timing of AD conversion, it is possible to synchronize AD conversion among a plurality of protection relays.

JP 2002-186166 (paragraph 0029, FIG. 1)

  In contrast to the conventional protection relay disclosed in Patent Document 1, the process bus-corresponding protection relay has a configuration in which, as described above, the MU having the main function of AD conversion and the IED that performs the relay operation are separated. When this process bus compatible protection relay is a PCM relay, PCM communication with other protection relays is performed by IED. That is, the PCM communication is executed by a unit different from the unit (MU) that performs AD conversion. As described above, the PCM relay needs to synchronize the AD conversion timing among a plurality of relays. However, when the PCM relay is a process bus compatible PCM relay, the MU and the IED are separated. The timing cannot be controlled, and AD conversion cannot be synchronized between a plurality of PCM relays.

  When controlling the AD conversion timing in the MU by transmitting a synchronization signal from the IED to the MU, there are the following problems. In consideration of the future use of the PCM relay corresponding to the process bus, that is, the replacement cycle, the MU and the IED may be manufactured by different manufacturers. If the MU and the IED are manufactured by the same manufacturer, the MU and the IED can be interconnected using a communication protocol unique to the manufacturer. However, considering that the exchange cycle of MU and IED is different, it is desirable that even those manufactured by different manufacturers of IED and MU can be interconnected without being restricted by the communication protocol. In the present situation where the IED and MU are made by different manufacturers and the synchronization signal from the IED to the MU is not considered, there is a high possibility that this synchronization signal hinders connection between different manufacturers. Since the MU replacement cycle is often installed in the vicinity of the main circuit such as the CT / PT and circuit breaker of the power system, for example, about 40 years, which is equal to the replacement cycle of the main circuit, is assumed. For IED, a replacement cycle (about 15 years) of the conventional protection relay is assumed.

  Furthermore, since the process bus compatible protection relay is connected between the IED and the MU via a LAN or a dedicated serial cable, the time from when the MU transmits data until the IED receives this data is constant for each PCM relay. It may not be. That is, even if the timing at which the IED receives data from the MU is the same among the PCM relays, the timing when the data is transmitted from the MU is not necessarily the same. Therefore, there is a problem that the relay calculation cannot be performed accurately unless the time from when the MU transmits data until the IED receives this data is taken into consideration.

  The present invention has been made in view of the above, and does not require a synchronization signal from the IED to the MU, and between the other protection relays even when the delay time of the network between the IED and the MU is not constant. An object of the present invention is to obtain a protection relay that can achieve stable PCM relay characteristics by synchronizing AD conversion.

  In order to solve the above-described problems and achieve the object, the present invention is a protection relay that protects a power system by converting analog data relating to system electricity into digital data, and is disposed in the power system and is externally connected. A counter value that is reset every time a synchronization signal is input and is cyclically counted up in a predetermined sampling period triggered by the synchronization signal is generated, and the analog data is AD in the sampling period. A first unit that outputs the converted data and the counter value, a process bus having one end connected to the first unit, and a second end connected to the other end of the process bus. Capture the converted data via the process bus and send / receive the data to / from other protection relays via the communication path A second unit for performing a relay operation for detecting a power grid fault, and the second unit manages the data transmitted to the other protection relay with an index number and manages the counter value. The maximum value is converted to a value smaller than the maximum value, and the data from the first unit is set in the transmission frame having the same index number as the cyclic value having the converted value as the maximum value. It transmits to the other protection relay.

  According to the present invention, the MU that generates a counter value that is reset every time a synchronization signal is input and that is cyclically counted up with a predetermined sampling period triggered by the synchronization signal, and the counter value to a small value. The process bus is connected to the IED that sets the AI data from the MU and transmits it to the other protection relay in the transmission frame having the same index number as the cyclic value with the maximum value after the conversion. Therefore, even if the synchronization signal from the IED to the MU is unnecessary and the delay time of the network between the IED and the MU is not constant, the AD conversion is synchronized with other protection relays and the PCM relay characteristics are stable. There is an effect that can be obtained.

FIG. 1 is a configuration diagram of a protection relay according to first to fifth embodiments of the present invention. FIG. 2 is a diagram in which the protection relay corresponding to the process bus shown in FIG. 1 is configured as a PCM relay. FIG. 3 is a diagram for explaining the counter value added by the MU according to the present embodiment. FIG. 4 is a diagram for explaining a method of synchronizing AI data between PCM relays according to the present embodiment. FIG. 5 is a diagram for explaining phase correction by the protection relay according to the second embodiment of the present invention. FIG. 6 is a diagram for explaining the counter value check operation by the protection relay according to the third embodiment of the present invention. FIG. 7 is a diagram for explaining the operation of the protection relay according to the fourth embodiment of the present invention. FIG. 8 is a diagram for explaining the operation of the protection relay according to the fifth embodiment of the present invention.

  Embodiments of a protection relay according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a protection relay according to first to fifth embodiments of the present invention, and this protection relay is a protection relay corresponding to a process bus. FIG. 2 is a diagram in which the protection relay corresponding to the process bus shown in FIG. 1 is configured as a PCM relay. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. Hereinafter, as the order of description, the configuration of the protection relay according to the present embodiment will be described first, and then the characteristic part of the present invention will be described.

  The protection relay according to the present embodiment includes an MU 1 (first unit) and an IED 11 (second unit) connected by a network line 7.

  The main function of the MU 1 is to convert analog data relating to the amount of electricity in the system into digital data, and send the AD-converted data (AI data) to the network line 7 at high speed. The network line 7 is a process bus that is a serial transmission medium, and a plurality of relays (not shown) such as PCM relays and overcurrent relays are connected to the network line 7. FIG. 1 shows an IED 11 that is a PCM relay as an example. The MU 1 is installed in the vicinity of the power transmission line so that AI data can be simultaneously transmitted to those relays.

  The IED 11 has a main function of performing PCM communication with other protection relays at high speed. The IED 11 can be used in a control room, a relay room, or the like so that an operator can change PCM settings or check the PCM status. is set up. The IED 11 captures AI data from the MU 1 via the process bus, and mutually transmits the AI data captured by the self-protection relay and the other protection relay via the PCM communication line (communication path) 17. And relay calculation which detects a power system fault is performed using each AI data of other protection relays.

  Thus, MU1 and IED11 can obtain stable PCM relay characteristics even when the network connection between MU1 and IED11 is complicated (a case where a plurality of MU1 and IED11 are connected to one network). It is configured to be able to. Hereinafter, the configurations of the MU 1 and the IED 11 will be specifically described.

  The MU 1 has, as main components, an input conversion unit 2 that takes in the amount of electricity from the power system, an analog input circuit 3, a multiplexer (MPX) 10, an AD converter 4, an arithmetic circuit 5, and a data transmission / reception circuit 6 And a time synchronization circuit 9. On the other hand, the IED 11 includes a data transmission / reception circuit 12, an arithmetic circuit 13, an output circuit 14, and a PCM transmission / reception circuit 16 as main components.

  The time synchronization circuit 9 is intended to accurately match the AD conversion timing in the AD converter 4 and is connected to the AD converter 4 and the arithmetic circuit 5. The time synchronization circuit 9 takes in a synchronization signal from the outside, and outputs a constant cycle pulse with the same timing. In the following description, a constant period pulse is referred to as a synchronization signal unless otherwise specified. The synchronization signal captured by the time synchronization circuit 9 is not particularly limited, and the most common means is a synchronization signal by GPS (Global Positioning System).

  The system electric quantity taken into the input conversion unit 2 is subjected to noise component removal by the analog filter (A / F) of the analog input circuit 3 and sampled by the sample hold circuit (S / H). The signals are alternately extracted and input to the AD converter 4.

  The AD converter 4 AD-converts the data from the multiplexer 10 at a predetermined timing by an unshown HW counter, and outputs the AD-converted data to the arithmetic circuit 5. The AD converter 4 is configured to reset the counter value at the timing when the synchronization signal is input, and to increment the counter value starting from the reset time. As described above, it is important that the AD conversion is executed at a timing that is not delayed from the time when the synchronization signal is input. When the synchronization signal from the time synchronization circuit 9 is taken into the AD converter 4 via the arithmetic circuit 5, the AD conversion start timing is delayed. The AD converter 4 according to the present embodiment is configured to start AD conversion at the timing when the synchronization signal is input by directly taking in the synchronization signal from the time synchronization circuit 9. Details of the counter value and the synchronization signal will be described in detail.

  Data converted into a digital signal by the AD converter 4 is input to the arithmetic circuit 5. The data input to the arithmetic circuit 5 is subjected to gain adjustment and phase correction as necessary, and sent to the data transmission / reception circuit 6. The data input to the data transmission / reception circuit 6 is transmitted to another unit (IED 11) through the network line 7. The network line 7 may be a network line such as a general LAN or a dedicated serial bus.

  Data transmitted from the MU 1 via the network line 7 is input to the data transmission / reception circuit 12. The arithmetic circuit 13 performs processing such as digital filter and effective value calculation on the data from the data transmission / reception circuit 12. Further, the arithmetic circuit 13 compares the data that has been subjected to the digital filter processing with predetermined set value data managed by the IED 11, and determines whether or not an accident has occurred in the power system.

  An output circuit 14 indicated by a dotted line is mounted on the IED 11, and this output circuit 14 indicates that an accident has occurred when the arithmetic circuit 13 determines that an accident has occurred on the power system. A predetermined signal (accident occurrence signal) is output to the outside. Note that the output circuit 8 can be mounted on the MU 1. In this case, the IED 11 transmits a signal for operating the output circuit 8 to the MU 1 via the network line 7 to operate the output circuit 8. . The data transmission / reception circuit 6 has a name corresponding to the function since a signal for operating the output circuit 8 may be fetched from the IED 11. However, when the output circuit 8 is unnecessary, the data transmission / reception circuit 6 is “data transmission circuit 6”. And shall be read as Similarly, since the data transmission / reception circuit 12 may transmit a signal for operating the output circuit 8 to the MU 1, the data transmission / reception circuit 12 has a name corresponding to the function. 12 ”.

  In FIG. 2, the PCM relay connection method includes a two-terminal method in which protection is performed by two PCM relays and a three-terminal method in which protection is performed by three PCM relays. However, since the configuration itself of the PCM relay is not different between the two terminals and the three terminals, the two-terminal system will be described here.

  The PCM transmission / reception circuit 16a connected to the arithmetic circuit 13a and the PCM transmission / reception circuit 16b connected to the arithmetic circuit 13b are interconnected by the PCM communication line 17, and receive the AI data taken into the self-protection relay and the other protection relay, respectively. Transmit to each other.

  Here, the conventional protection relay measures the transmission delay time between the relays, performs control so that the AD conversion timing is the same between the relays, and transmits the AI data transmitted to the other protection relay and the other protection. Control is performed so that AI data from a relay having the same AD conversion timing can be handled as sampling data at the same timing.

  Furthermore, in the conventional protection relay, if the upper SW (PCM relay application software) sets data at the latest address of the PCM transmission frame, synchronization can be achieved among a plurality of PCM relays. More specifically, the IEDs synchronize between a plurality of PCM relays, and PCM communication is possible by setting the latest AI data in a transmission frame every period. However, in the process bus compatible protection relay, the MU and the IED are not integrally installed, so the IED cannot control the AD conversion of the MU.

  The protection relay according to the present embodiment is configured such that the AD conversion timing is the same between the relays even if the IED 11 cannot control the AD conversion of the MU1. Hereinafter, the processing content of the protection relay according to the present embodiment will be described in detail.

  FIG. 3 is a diagram for explaining the counter value added by the MU 1. FIG. 3 shows processing operations performed by the AD converter 4 and the arithmetic circuit 5. The MU 1 according to the present embodiment is configured to reset the counter value at the timing when the synchronization signal is input, start AD conversion starting from the time when the counter value is reset, and count up each time AD conversion is performed. Has been. Hereinafter, the relationship between the synchronization signal and the counter value will be specifically described.

  First, the timing at which the counter value is reset is, for example, once per second when GPS synchronization is established. This GPS synchronization is performed by a synchronization signal from the time synchronization circuit 9. The counter value is reset by the arithmetic circuit 5, for example, and the AD converter 4 is configured to start AD conversion upon detecting that the arithmetic circuit 5 has reset the counter value.

  Next, the AD conversion interval (sampling period) is specified by a HW counter (not shown) inside the MU 1 and is, for example, 0.25 ms (electrical angle 4.5 °). The AD converter 4 samples the AI data taken in via the multiplexer 10 at this cycle. FIG. 3 shows the GPS synchronization interval and the sampling period. In the example of FIG. 3, the time from the counter reset (counter value = 0) to the counter value = 1 is 0.25 ms, and the counter value = 0. The time from the counter value to 2 is 0.5 ms. On the other hand, the time from when the first GPS synchronization signal is input (when the counter value = 0) until the second GPS synchronization signal is input is 1 second. When the system power amount of 50 Hz is sampled at an electrical angle of 4.5 °, the counter value is incremented 3999 times between the input of the first GPS synchronization signal and the input of the next GPS synchronization signal. . That is, the AD converter 4 performs 3999 AD conversions per second. In the protection relay according to the present embodiment, the sampling period is 0.25 ms as an example, but the present invention is not limited to this.

  In this way, the MU 1 generates a counter value that is reset every time an external synchronization signal is input and that is cyclically counted up at a predetermined sampling period (0.25 ms) using the synchronization signal as a trigger. At the same time, the analog data is AD-converted at the sampling period and the counter value is sent to the network line 7.

  Next, processing contents in the IED 11 will be described.

  FIG. 4 is a diagram for explaining a method of synchronizing AI data between PCM relays according to the present embodiment. Assume that the AI data synchronization processing is performed by the arithmetic circuit 13. 4 does not show elements such as the AD converter 4 shown in FIGS. 1 and 2 for convenience of explanation, but the IED 11 shown in FIG. 4 stores AI data with other protection relays. A transmission frame for PCM relay and a reception frame for PCM relay for transmission and reception are conceptually shown. The IED 11 manages the AI data transmitted to the other protection relays with an index number, converts the maximum counter value from the MU 1 to a value smaller than the maximum value, and sets the converted value as the maximum value. The AI data from the MU 1 is set in the transmission frame having the same index number as the cyclic value to be transmitted and transmitted to the other protection relay. Details will be described below.

  The transmission frame indicates a frame of AI data transmitted to the other protection relay, and the reception frame indicates a frame of AI data received from the other protection relay. The AI data transmitted to the other protection relay and the AI data received from the other protection relay are temporarily stored in a memory (not shown). In FIG. 4, as an example, 12 frames are prepared for each. The reason why the number of transmission frames and reception frames is 12 will be described later.

  An index number indicated by 0 to 11 is given to the transmission frame, and a similar index number is given to the reception frame. This index number is based on a remainder value obtained by dividing the counter value by the number of transmission frames (or reception frames). For example, the remainder when the counter value “3955” is divided by the number of frames “5” is “11”, and the remainder when the counter value “3996” is divided by the number of frames “6” is “0”. is there. In the above example, the counter value is a cyclic value that is incremented by 1 for each AD conversion. By dividing this counter value by the number of frames, a cyclic value of 0 to 11 is obtained. Therefore, the index number assigned to each frame can be represented by a value from 0 to 11. In this way, by dividing the counter value by the number of frames, it is possible to manage AI data generated 3999 times per second with 12 transmission frames.

  Here, the main function of the MU 1 is to send synchronized AD conversion data to the IED 11 at a high speed using a synchronization signal as a trigger, and the main function of the IED 11 is to perform PCM communication with other protection relays. Thus, by sharing the main functions, it is possible to obtain an accurate PCM relay characteristic. However, since the MU1 and the IED11 are connected by the process bus in the process bus compatible protection relay, when the MU1 transmits AI data to the IED11, the delay in the network line 7 may affect the PCM relay characteristics. is there. It is also possible to execute PCM communication such that the number of AI data transmitted at the interval of the synchronization signal (3999 in the above example) and the number of transmission frames have a one-to-one relationship. However, in this case, not only the memory of the IED 11 is increased, but also speeding up of the PCM communication can be hindered.

  The protection relay according to the present embodiment is reset every time a synchronization signal is input, and generates a counter value that is cyclically counted up at a predetermined sampling period using the synchronization signal as a trigger, and the counter value Is converted to a cyclic value smaller than the counter value, and the IED 11 sets AI data in a transmission frame having the same index number as the cyclic value. Therefore, even when AI data transmitted on the network line 7 is delayed, AD conversion can be synchronized with other protection relays, and PCM can be performed at high speed without increasing the memory of the IED 11. Communication is possible.

  The reason why the number of transmission frames and reception frames is set to 12 is that the memory inside the IED 11 is suppressed from being excessive, and the transmission delay of AI data in the network line 7 is rarely 12 frames or more. Because it is considered. However, the number of frames is not limited to this, and it is sufficient that the maximum value of the cyclic index number is smaller than the maximum value of the counter value. For example, the same effect can be obtained even in the range of several tens to several hundreds.

  The overall operation will be described below.

  First, a scene in which AI data is transmitted from the IED 11a to the IED 11b will be described. The MU 1a transmits AI data and a counter value to the IED 11a. The counter value is assumed to be “3996”, for example, and the data AD-converted at the timing of this counter value is assumed to be “XXXX”. The data “XXXX” and the counter value “3996” are transmitted to the network line 7a, and the IED 11a transmits the index number “0” corresponding to the remainder obtained by dividing the counter value “3996” by the number of transmission frames “12”. Data “XXXX” is set in the frame.

  Here, in transmission / reception of PCM data between the IED 11a and the IED 11b, the numbers on the transmission frame and the numbers on the reception frame correspond one-to-one. For example, data transmitted to the IED 11b in the nth transmission frame in the IED 11a is set in the nth reception frame of the IED 11b. To explain using the above example, the data “XXXX” transmitted to the IED 11b in the “0” th transmission frame in the IED 11a is set in the “0” th reception frame in the IED 11b. Since the counter value is incremented for each AD conversion, when there are 12 transmission frames, the transmission frame makes a round by 12 AD conversions.

  Next, a scene in which AI data is transmitted from the IED 11b to the IED 11a will be described. The MU 1b adds a counter value to the AD-converted data (AI data) and transmits it to the IED 11b. The counter value is “3996” as described above. The data AD-converted at the counter value timing is assumed to be “XXXY” for convenience of explanation. The data “XXXY” and the counter value “3996” are transmitted to the network line 7b, and the IED 11b transmits the index number “0” corresponding to the remainder obtained by dividing the counter value “3996” by the number of transmission frames “12”. Data “XXXY” is set in the frame. As a result, the data “XXXX” is stored as data with the index number “0” in the reception frame of the IED 11b, and the data “XXXY” is stored as data with the index number “0” in the transmission frame of the IED 11b. It becomes.

  Since the AI data with the same index number is AD-converted data at the same time, the IED 11a and IED 11b treat them as AI data at the same timing, and perform operations as PCM relays (relay operations such as accident detection). Do.

  It is assumed that the time until the data processed by the local IED (for example, IED 11a) is transmitted to another IED (IED 11b) exceeds the size of the transmission frame (12 frames in the above description). For example, when the number of frames is m, the time (t1) that the data processed by the IED 11a reaches the IED 11b after the data AD-converted by the MU 1a is received by the IED 11a via the network line 7a However, if it is smaller than “sampling period × m”, there is basically no problem. When the numerical values described above are used, the “sampling period” is 0.25 ms and the number of frames “m” is 12, so there is no problem if the time t1 is 3 ms (0.25 ms * 12) or less. As another example, when the “sampling period” is 0.25 ms and the number of frames “m” is 2, there is no problem if the time t1 is 0.5 ms (0.25 ms * 2) or less.

  As described above, the protection relay according to the present embodiment has a counter value that is reset every time a synchronization signal is input and that is cyclically counted up at a predetermined sampling period using the synchronization signal as a trigger. Generate and convert the maximum counter value to a value smaller than this maximum value, and set the AI data from MU1 in the transmission frame having the same index number as the cyclic value with the converted value as the maximum value. Thus, even if the AI data transmitted on the network line 7a is delayed from the AI data transmitted on the network line 7b, the IED 11a and the IED 11b transmit the GPS synchronization signal. The same index number can be obtained based on the counter value used as a trigger. Therefore, the protection relay according to the present embodiment does not require a synchronization signal from the IED 11 to the MU 1, and AD conversion is performed between other protection relays even when the delay time of the network between the IED 11 and the MU 1 is not constant. Therefore, stable PCM relay characteristics can be realized.

Embodiment 2. FIG.
In the protection relay for process buses, it is assumed that IED and MU are manufactured by different manufacturers. In particular, in the case of a process bus compatible PCM relay, for example, the MU connected to one IED is manufactured by A company, but the MU connected to another IED may be manufactured by B company. When IED and MU are all the same manufacturer, the delay time from the timing when the AD conversion command is issued to the timing when the AD conversion is actually performed is approximately constant. Therefore, in this case, even with the method of the first embodiment, it is possible to handle data AD-converted at the same timing between a plurality of IEDs. However, when MUs of different manufacturers are used, the delay time may be different for each manufacturer. The IED 1 according to the present embodiment is configured to perform phase correction on AI data from the MU 1 when the delay time of each MU 1 is clear.

  FIG. 5 is a diagram for explaining the phase correction by the protection relay according to the second embodiment of the present invention, and shows the difference in delay time of AD conversion timing in each MU of different manufacturers. MU1 shown by FIG. 5 is MU made from A company, for example, and MU2 is MU made from B company. MU1 has a delay time of α with respect to the synchronization signal, and MU2 has a delay time of β with respect to the synchronization signal. In this case, there is a difference of (β−α) between the AD conversion timings.

  The IED 1 according to the present embodiment is configured to correct the phase of AI data so as to eliminate the difference of (β−α) when the delay time of each MU 1 is clear. For example, when MU1 (MU1a) is connected to IED11a and MU2 (MU1b) is connected to IED11b, in the above case, IED11b performs (β−α) phase correction on AI data from MU1b. Just do it. In this way, AI data from the MU 1a and AI data from the MU 1b can be handled as AI data at the same timing.

  This phase correction value can be set in each IED 11, and the phase correction formula uses a formula that uses a plurality of sampling data generally used. Further, this phase correction may be performed by, for example, the arithmetic circuit 13, or a mode in which new correction means is provided in the IED 11 and executed.

  The operation will be described below. The MU 1a starts AD conversion at the timing of the delay time α, and the IED 11a sets AI data in the transmission frame having the index number based on the counter value from the MU 1a. The MU 1b executes AD conversion at the timing of the delay time β, and the IED 11b performs phase correction for (β−α) of the AI data, and also performs phase correction on the transmission frame of the index number based on the counter value from the MU 1b. The later AI data is set.

  As described above, the protection relay according to the present embodiment has a delay time α between the time when a synchronization signal is input and the start of AD conversion in one protection relay, and in other protection relays. When the delay time β is longer than the delay time α and the AD conversion is started after the synchronization signal is input, the second unit of the other protection relay (for example, the IED 11b) Since the phase correction for (β−α) is performed on the AI data from the first unit (for example, MU1b) of the protection relay, the AI having a difference of (β−α) in AD conversion timing It is possible to handle the data as AI data that has been AD-converted at the same timing and perform a relay operation. As a result, not only the effects according to the first embodiment, but also stable PCM relay characteristics can be obtained even when connecting between different manufacturers.

Embodiment 3 FIG.
The IED 11 according to the first and second embodiments uses the counter value from the MU 1 to synchronize the AI data with each other. For this reason, if the counter value becomes an incorrect value, a serious result such as a relay malfunction may occur. The IED 11 according to the present embodiment is configured to always check the continuity of the counter value from the MU 1 and to perform processing such as relay lock if the continuity is impaired. Note that the relay lock means that the relay calculation is locked.

  FIG. 6 is a diagram for explaining the counter value check operation by the protection relay according to the third embodiment of the present invention. In FIG. 6, the continuity of the counter value transmitted from the MU 1 to the IED 11 is impaired. The state is shown. For example, the counter value 1007 is a counter value received by the IED 11 five times before. Similarly, the counter value 1008 is the counter value received by the IED 11 four times before, and the counter value 1011 is the counter value received by the IED 11 one time before.

  Thus, the IED 11 continuously receives the counter value incremented by one. However, the counter value may become an incorrect value due to an error during transmission from the MU1. For example, the counter value of “current” shown in FIG. 6 should be 1012 if it should be, but is 1013 due to the loss of continuity. When the counter value is 1012, the index number is 4 (the number of frames is 12), but when the counter value is 1013, the index number is 5.

  As described in the first embodiment, in the transmission / reception of PCM data between the IED 11a and the IED 11b, the number on the transmission frame and the number on the reception frame correspond one-to-one. However, for example, when the continuity of the counter value from the MU 1a is lost, the IED 11a stores the AI data of the counter value 1013 received after the counter value 1011 in the transmission frame with the index number 5. On the other hand, when the continuity of the counter value from the MU 1b is maintained, the IED 11b stores the AI data of the counter value 1012 received after the counter value 1011 in the transmission frame of the index number 4. As a result, the circuit breaker may be accidentally interrupted.

  The IED 11 according to the present embodiment is configured to perform processing such as relay lock when the continuity of the counter value is impaired. The continuity check may be performed by the arithmetic circuit 13 or may be executed by providing a new detection unit in the IED 11.

  The operation will be described below. The MU 1a performs AD conversion, and the IED 11a sets AI data in a transmission frame having an index number based on the counter value from the MU 1a. On the other hand, the MU 1b executes AD conversion, and the IED 11b sets AI data in a transmission frame having an index number based on the counter value from the MU 1b. Here, when the continuity of the AI data that has reached the IED 11b is impaired, the IED 11b detects that the continuity of the counter value is impaired and performs relay lock.

  As described above, in the protection relay according to the present embodiment, the IED 11 (second unit) locks the relay calculation when the continuity of the counter value from the MU 1 (first unit) is impaired. Thus, in addition to the effects of the first and second embodiments, stable PCM relay characteristics can be obtained even when the continuity of the counter value is impaired.

  Note that the protection relay according to the present embodiment can be combined with the phase correction processing by the IED 11 according to the second embodiment.

Embodiment 4 FIG.
The first to third embodiments have been described on the premise that the sampling periods (0.25 ms in the first embodiment) in each MU 1 are the same. However, when MU1s made by different manufacturers are connected to the IED 11, the sampling period in each MU1 may be different. Here, it is assumed that the sampling period is the other MU1 whose sampling period is an integer (n) times the predetermined MU1. Specifically, one MU1 has a sampling period of 1 ms, for example, and increments the counter value by 1 every 1 ms, while the other MU1 has a sampling period of 5 ms, for example, and n = 5 The counter value may be incremented by 1 every 5 ms. In this case, the counter values received by the respective IEDs 11 do not match each other, so that it is difficult to handle them as PCM relays. The protection relay according to the present embodiment is configured so that the progress of the counter value when viewed from the IED 11 is the same even when each MU 1 counts up the counter value by one for each unique sampling period. Yes.

  FIG. 7 is a diagram for explaining the operation of the protection relay according to the fourth embodiment of the present invention. The upper side of FIG. 7 shows a counter value that is incremented by 1 for each sampling period, where the sampling period in the MU 1a is 1 ms. The lower part of FIG. 7 shows a counter value that is incremented by 5 for each sampling period, where the sampling period in MU 1b is 5 ms with n = 5. In this case, it can be seen that the counter values of MU1a and MU1b are increased by 5 in 5 ms.

  For example, when considering a counter value after 5 ms from the time when the counter value is 1010, MU1a increments the counter value by 1 every 1 ms, and MU1b increments the counter value by 1 every 5 ms. The counter value of MU1a is 1015, but the counter value of MU1b after 10 ms is 1011. That is, the counter value in MU1a after the elapse of a predetermined time and the counter value in MU1b are different values. The MU 1 according to the present embodiment is configured to be able to set how the counter value advances (may be referred to as an increase amount) for each AD conversion.

  The adjustment of the counter value may be performed by the arithmetic circuit 5, or a counter value correction unit (not shown) is provided in the MU 1, and the counter value correction unit is supplied from the arithmetic circuit 5. The counter value may be adjusted and sent to the network line 7.

  The operation will be described below. The MU 1a executes AD conversion every 1 ms, and increments the counter value by 1 at the AD conversion timing, and the IED 11a sets AI data in the transmission frame having the index number based on the counter value from the MU 1a. On the other hand, the MU 1b executes AD conversion every 5 ms and increments the counter value by 1 at the AD conversion timing. Here, when the counter value is incremented by one, MU1b is a value obtained by dividing the sampling cycle (5 ms) of MU1b by the sampling cycle (1 ms) unique to MU1a for each sampling cycle (5 ms) of MU1b (n = 5). ) Is subtracted by 1 (n-1 = 4) and added to the counter value of the other protection relay and output to the IED 11b. Then, the IED 11b sets AI data in a transmission frame having an index number based on the counter value from the MU 1b.

  As described above, in the protection relay according to the present embodiment, in one protection relay, the counter value is incremented by 1 at a sampling period unique to one protection relay, and in the other protection relays, the sampling of one protection relay is performed. If the counter value is incremented by 1 with a sampling period that is n times longer than the period, the first unit of the other protection relay (for example, MU1b) has one protection relay specific for each sampling period of the other protection relay. Since the value n−1 = 4 after subtracting 1 from the value n = 5 obtained by dividing the sampling period peculiar to other protection relays by the sampling period is added to the counter value of the other protection relay. It is possible to obtain stable PCM relay characteristics even if each MU1 is made by a different manufacturer. It is.

  The protection relay according to the present embodiment can be combined with the phase correction processing according to the second embodiment, or can be combined with the relay lock function according to the third embodiment. Further, in order to extend this concept and synchronize units whose sampling periods are Kms and Lms, the sample values that are synchronized every period Mms by the least common multiple M of K and L are assigned to the same counter value, and the same index It is also possible to set a transmission frame with a number.

Embodiment 5 FIG.
As described in the fourth embodiment, the AD conversion interval of MU1 may be different. In the fourth embodiment, the progress of the counter value when viewed from the IED is matched by the MU adjusting the progress of the counter value. The protection relay according to the fifth embodiment adjusts the counted-up counter value on the IED side when the counter value generated by the MU is incremented by one as in the first to third embodiments. Is configured to do. In other words, the protection relay according to the fourth embodiment is an aspect that adjusts the count value with the longer sampling period, and the protection relay according to the fifth embodiment adjusts the counter value with the shorter sampling period. It is an aspect.

  FIG. 8 is a diagram for explaining the operation of the protection relay according to the fifth embodiment of the present invention. The protection relay according to the present embodiment is configured such that the IED 11 converts the counter value in accordance with the MU (MU3 in FIG. 8) in which the counter value advances most slowly.

  For example, assume that the sampling period of MU1 (MU1a) is 1 ms, the sampling period of MU2 (MU1b) is 2 ms, and the sampling period of MU3 is 6 ms. In this case, the counter value of the IED 11a connected to the MU 1a is counted up at a speed six times that of the IED (not shown) connected to the MU 3. Similarly, the counter value of the IED 11b connected to the MU 1b is counted up three times faster than the IED connected to the MU 3.

  The IED 11a according to the present embodiment changes the counter value so that the counter value becomes 1/6 according to the MU3 in which the counter value advances the slowest. Similarly, the IED 11b changes the counter value so that the counter value becomes 1/3 according to MU3. Specifically, the MU 1a calculates a value A (6) obtained by dividing the sampling period (6 ms) of the MU 3 by its own sampling period (1 ms), and divides the own counter value (1806) by this value A (6). A new counter value (301) is generated. Similarly, MU1b calculates a value B (3) obtained by dividing the sampling period (6ms) of MU3 by its own sampling period (2ms), and divides its own counter value (903) by this value B (3). A counter value (301) is generated. As described above, the IED 11 converts the counter value in accordance with the MU 3 with the latest counter value advancement, so that it can be easily handled as a PCM relay.

  The operation of the protection relay according to the present embodiment will be described using MU1 (MU1a), MU2 (MU1b), and MU3 described above. First, the MU 3 executes AD conversion every 6 ms, and increments the counter value by 1 at the AD conversion timing. The IED connected to the MU 3 transmits the index number based on the counter value from the MU 3 to the transmission frame. Set AI data.

  On the other hand, the MU 1a executes AD conversion, for example, every 1 ms, and increments the counter value by 1 at the AD conversion timing. Here, the MU 1a calculates a value A obtained by dividing the sampling period of the MU 3 by its own sampling period, and divides the own counter value by A to generate a new counter value. The IED 11a sets AI data in a transmission frame having an index number based on a new counter value from the MU 1a.

  Similarly, MU1b calculates a value B obtained by dividing the sampling period of MU3 by its own sampling period, and divides its own counter value by B to generate a new counter value. The IED 11b sets AI data in a transmission frame having an index number based on a new counter value from the MU 1b.

  As described above, the protection relay according to the present embodiment has different AD conversion sampling periods in a plurality of protection relays, and each counter value is incremented by 1 with a unique sampling period. The second unit of the protection relay other than the protection relay having the longest sampling period among the protection relays (for example, MU1 and MU2 in FIG. 8) has its own counter at every sampling period (6 ms) of the protection relay having the longest sampling period. Since the value is converted to the same value as the counter value (301) of the protection relay with the longest sampling period, for example, even if each MU1 to 3 are made by different manufacturers, Stable PCM relay characteristics can be obtained.

  The protection relay according to the present embodiment can be combined with the phase correction processing according to the second embodiment, or can be combined with the relay lock function according to the third embodiment.

  In addition, although the protection relay concerning Embodiment 1-5 is the structure at the time of applying to the PCM relay corresponding to a process bus, it is not limited to this. For example, the processing operations in the arithmetic circuit 5 and the arithmetic circuit 13 described in the first to fifth embodiments can be applied to a protection relay in which an AD conversion unit and a PCM communication unit are integrally configured. is there.

  In addition, the protection relay shown in Embodiments 1 to 5 shows an example of the content of the present invention, and can be combined with another known technique, and does not depart from the gist of the present invention. Of course, it is possible to change the configuration such as omitting a part of the range.

  As described above, the present invention can be applied to a protection relay that protects a power system by converting analog data related to the amount of electricity in the system into digital data, and in particular, there is no synchronization signal from the IED to the MU Even when the delay time of the network between the IED and the MU is not constant, the present invention is useful as an invention capable of obtaining stable PCM relay characteristics by synchronizing AD conversion with other protection relays.

1, 1a, 1b MU (first unit)
2, 2a, 2b Input conversion unit 3, 3a, 3b Analog input circuit 4, 4a, 4b AD converter 5, 5a, 5b Arithmetic circuit 6, 6a, 6b Data transmission / reception circuit 7, 7a, 7b Network line (process bus)
8, 8a, 8b Output circuit 9, 9a, 9b Time synchronization circuit 10, 10a, 10b Multiplexer 11, 11a, 11b IED (second unit)
12, 12a, 12b Data transmission / reception circuit 13, 13a, 13b Arithmetic circuit 14, 14a, 14b Output circuit 16, 16a, 16b PCM transmission / reception circuit 17 PCM communication line (communication path)

Claims (6)

A protection relay that protects the power system by converting analog data related to grid electricity into digital data,
A counter value that is arranged in a power system, is reset whenever an external synchronization signal is input, and is cyclically counted up in a predetermined sampling period using the synchronization signal as a trigger, and the analog data A first unit that outputs data obtained by AD conversion at the sampling period and the counter value;
A process bus having one end connected to the first unit;
Connected to the other end of the process bus, fetches the data AD-converted by the first unit via the process bus, and transmits / receives the data to / from other protection relays via a communication path. A second unit for performing a relay operation to detect a system fault;
With
The second unit manages the data to be transmitted to the other protection relay with an index number, converts the maximum value of the counter value to a value smaller than the maximum value, and converts the converted value to In the transmission frame with the same index number as the cyclic value that is the maximum value, the data from the first unit is set and transmitted to the other protection relay ,
In one protection relay, the counter value is incremented by 1 in a sampling period unique to the one protection relay, and in the other protection relay, the counter value is incremented by 1 in a sampling period that is an integral multiple of the sampling period of the one protection relay. If incremented,
The first unit of the other protection relay has an integer value obtained by dividing the sampling period specific to the other protection relay by the sampling period specific to the one protection relay for each sampling period of the other protection relay. A protection relay, wherein a value after subtraction is added to the counter value of the other protection relay.   The second unit sets the data from the first unit in a transmission frame having the same index number as a remainder value obtained by dividing the counter value from the first unit by the number of transmission frames. The protection relay according to claim 1.   The protection relay according to claim 1, wherein the synchronization signal is a GPS signal. One protection relay has a delay time α between the input of the synchronization signal and the start of AD conversion, and the other protection relay has a time longer than the delay time α and the synchronization signal is input. In the case where a delay time β is included between the start time and AD conversion start,
The second unit of the other protection relay performs phase correction for (β-α) on the data from the first unit of the other protection relay. The protection relay as described in any one of -3.   The said 2nd unit locks the said relay calculation, when the continuity of the said counter value from the said 1st unit is impaired, The any one of Claims 1-4 characterized by the above-mentioned. Protection relay. When the AD conversion sampling periods in the plurality of protection relays are different from each other, and the counter value is incremented by 1 at each unique sampling period,
The second unit of the protection relay other than the protection relay having the longest sampling cycle among the plurality of protection relays has its own counter value for each sampling cycle of the protection relay having the longest sampling cycle. The protection relay according to any one of claims 1 to 5 , wherein the protection relay is converted to the same value as a counter value of the longest protection relay.

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