Merging unit and protection relay system

Abstract

To provide a merging unit and a protection relay system that can build an appropriate synchronization system in a digital substation.SOLUTION: A MU has an input conversion circuit that takes in analog information of a power system, and first and second arithmetic substrates. The first arithmetic substrate comprises a circuit unit that generates a first sampling timing, a first A / D conversion unit that performs conversion at the first sampling timing, and a first transmission unit that transmits first digital data. The second arithmetic substrate comprises a circuit unit that generates a second sampling timing, a second A / D conversion unit that performs conversion at the second sampling timing, and a second transmission unit that transmits second digital data. Time synchronization of the first sampling timing is performed with a first master clock. Time synchronization of the second sampling timing is performed with a second master clock different from the first master clock.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a merging unit and a protection relay system. [Background technology]

[0002] In recent years, research into digital networking of substations (hereinafter referred to as digital substations) has been progressing with the aim of reducing costs by streamlining substation equipment. In a digital substation, the merging unit (MU) with input / output sections is separated from the intelligent electronic device (IED) with the calculation section, unlike the protective relay devices that were previously configured on the same panel, and the merging unit is placed near the main unit, thereby replacing the large number of metal cables connecting the main unit and the protective control devices with a small number of optical cables. In the following description, the intelligent electronic device is referred to as an IED and the merging unit as an MU.

[0003] In a digital substation, the IEDs and MUs transmit and receive analog information and equipment status information measured by the MUs and processed information calculated by the IEDs via a process bus using data communications based on the IEC (International Electrotechnical Commission) 61850 standard.

[0004] In the current differential method in a protective relay system, in order to determine whether a system fault has occurred within the protection section, the current measured by the device itself and the current measured by the other device are transmitted and received between them, the differential current is calculated from the transmitted and received current values, and the system fault within the protection section is determined based on the magnitude of the differential current. To accurately identify grid faults, all devices in the system must use simultaneously sampled current data. This means that in a digital substation, the MUs that measure analog information must synchronize their sample timing with high precision.

[0005] To ensure highly accurate sampling synchronization, sampling synchronization control is generally performed using time synchronization. There are various known time synchronization protocols, such as NTP (Network Time Protocol), SNTP (Simple Network Time Protocol), and PTP (Precision Time Protocol).

[0006] PTP is a method defined by the IEEE (Institute of Electrical and Electronics Engineers) 1588 standard. PTP defines a communication protocol for time frames between a device that serves as the reference for time synchronization (hereafter referred to as the master clock) and the device to be synchronized. Time frames are sent and received via a communication path between the master clock and the device, and the device's time offset relative to the master clock is calculated and the device's time is corrected.

[0007] The protection relay system comprises a substation protection relay system represented by a busbar protection relay and a transformer protection relay, and an inter-substation protection relay system represented by an IP-PCM (Internet Protocol Pulse Code Modulation) current differential protection relay, etc. Therefore, the time synchronization of the protection relay system in a digital substation needs to be calibrated not only within the substation but also between substations.

[0008] Patent Document 1 describes a protective relay system in which each terminal of a plurality of protective relays is connected to a power transmission line via a switching hub with a PTP time synchronization function, and each protective relay is provided with a transmission and sampling synchronization control unit in order to synchronize the sampling timing of the system's electrical quantities between the protective relays. The technology described in Patent Document 1 performs relay calculations based on sampling synchronization information.

[0009] Furthermore, Patent Document 2 describes a technology in which, in a sampling control method switching unit, a delay time difference measurement unit, a first time synchronization correction unit, and a second time synchronization correction unit provided in a digital protective relay, if the communication delay time is greater than a predetermined value, the first time synchronization correction unit is switched to the second time synchronization correction unit to perform time synchronization correction calculations. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2018-102043 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-189074 Summary of the Invention [Problem to be solved by the invention]

[0011] However, the technologies described in Patent Documents 1 and 2 take into consideration the synchronization system required to realize a conventional inter-substation protection relay system, and in a digital substation, it is necessary to comprehensively consider both the system within the substation and the systems between substations.

[0012] One method for synchronizing digital substations is to install a master clock at each substation and at the other substation, synchronize the master clocks using the Global Navigation Satellite System (GNSS), and create a system-wide synchronization network that spans the substations. However, this method has many issues, such as the large scope of impact in the event of a GNSS failure, the need for security measures for GNSS signals, and the increased costs of installing GNSS receivers.

[0013] Another example is to install separate MUs for the substation protection relay system and the inter-substation protection relay system. In this example, the MU for the substation protection relay system has a master clock installed in the substation itself, while the MU for the inter-substation protection relay system has a master clock dedicated to the inter-substation protection relay system, creating separate synchronization networks for each. Note that in this case, the master clock is the internal clock of the main station IED. However, the above method also raises concerns about increased costs due to an increase in MU, and cannot be said to be an efficient system configuration.

[0014] Furthermore, because conventional protective relay systems are systems that extend not only within a substation but also between substations, problems arise when there is a difference in the timing of the upgrade to digital substations (applying IEC 61850) between the local substation and the opposing substation. In other words, if there is a difference in the timing of the upgrade to digital substations, it will be impossible to switch from the conventional protective relay system until both substations are upgraded to digital substations, and there is a concern that it will take a long time before the inter-substation protective relay system applying IEC 61850 can begin operation.

[0015] An object of the present invention is to provide a merging unit and a protective relay system that can construct an appropriate synchronization system in a digital substation. [Means for solving the problem]

[0016] In order to solve the above problems, for example, the configurations described in the claims are adopted. The present application includes a plurality of means for solving the above-mentioned problems. One example of such a means is a merging unit having an input conversion board that takes in analog information of the power system from a main unit, a first calculation board, and a second calculation board, the first arithmetic board comprises a circuit unit that generates a first sampling timing, a first A / D conversion unit that digitally converts an analog output signal of the input conversion board at the first sampling timing, and a first transmission unit that transmits the first digital data; the second arithmetic board includes a circuit unit that generates a second sampling timing, a second A / D conversion unit that digitally converts an analog output signal of the input conversion board at the second sampling timing, and a second transmission unit that transmits the second digital data; The first sampling timing is time-synchronized with a first master clock, and the second sampling timing is time-synchronized with a second master clock that is different from the first master clock. [Effects of the Invention]

[0017] According to the present invention, it is possible to construct a synchronized system for realizing the functions of both a substation premises protection relay system and an inter-substation protection relay system in a digital substation, and to provide a protection relay system that is highly economical and reliable. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a block diagram showing an example of the configuration of an MU according to a first embodiment of the present invention. [Figure 2] 1 is a block diagram showing an example of a configuration for generating sampling timing of a transmission processing circuit according to a first embodiment of the present invention; [Figure 3] 1 is a system configuration diagram showing an example in which both a local substation and an opposing substation are digital substations according to a first embodiment of the present invention. FIG. [Figure 4] FIG. 10 is a system configuration diagram showing an example of a case where only the local substation is digital according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Merging units and protection relay systems according to embodiments of the present invention will be described below with reference to the accompanying drawings. In each embodiment, the same components are generally designated by the same reference numerals, and repeated explanations will be omitted. Note that each embodiment described below is merely an example for realizing the present invention, and does not limit the technical scope of the present invention.

[0020] <First embodiment> A first embodiment of the present invention will be described below with reference to FIGS. In this embodiment, both the local substation and the opposing substation are applied to a digitalized protection relay system in accordance with the international standard IEC61850.

[0021] [Merging Unit (MU) Configuration] The configuration of the merging unit (MU) 1 in this embodiment will be described with reference to FIGS. FIG. 1 is a block diagram showing the configuration of the MU 1. FIG. 2 is a block diagram for explaining the sampling timing generation process in the transmission processing circuits 1332 and 1432 of the MU1.

[0022] As shown in FIG. 1, the MU1 is composed of an input conversion board 11, an output board 12, an operation board 13, and an operation board . The input conversion board 11 receives analog information (current and voltage) of the power system from a main unit (for example, a gas-insulated switchgear) via a control cable. The operation board 13 is composed of an analog filter 131, an A / D (Analog to Digital) conversion unit 132, an integrated circuit unit 133, and a communication IF (interface) 15. The operation board 14 is composed of an analog filter 141, an A / D conversion unit 142, an integrated circuit unit 143, and a communication IF 16.

[0023] The output signal from the input conversion board 11 is input to analog filters 131 and 141. The analog filters 131 and 141 have, for example, low-pass filter characteristics and function as band-limiting filters for preventing aliasing errors due to sampling. The A / D conversion unit 132 receives the output signal of the analog filter 131 as input and performs sampling at a specific cycle to convert analog information into digital information. The first sampling timing in the A / D conversion unit 132 is synchronously corrected based on a clock counter synchronized with the first master clock by PTP packet information transmitted and received. In the following explanation and drawings, the first sampling timing will be referred to as sampling timing (1), and the first master clock will be referred to as master clock (1).

[0024] Similarly, the A / D conversion unit 142 receives the output signal of the analog filter 141 as input and performs sampling at a specific cycle to convert analog information into digital information. The second sampling timing in the A / D conversion unit 142 is synchronously corrected based on a time counter synchronized with the second master clock by PTP packet information transmitted and received. In the following explanation and drawings, the second sampling timing will be referred to as sampling timing (2), and the second master clock will be referred to as master clock (2). The digital information converted by the A / D conversion units 132 and 142 is input to the integrated circuit units 133 and 143, respectively.

[0025] The integrated circuit unit (circuit unit) 133 is composed of an arithmetic processing unit 1331 and a transmission / reception circuit 1332 , and the integrated circuit unit 143 is composed of an arithmetic processing unit 1431 and a transmission / reception circuit 1432 . The arithmetic processing unit 1331 performs predetermined processing on the data that has been digitally converted by the A / D conversion unit 132. For example, the arithmetic processing unit 1331 generates SV (Sampled Value) data defined in the international standard IEC61850 and performs SV transmission processing. In the SV transmission process, the arithmetic processing unit 1331 instructs the transmission / reception circuit 1332 to transmit SV data via the communication IF 15. Similarly, the arithmetic processing unit 1431 performs predetermined processing on the data digitally converted by the A / D conversion unit 142, for example, to generate SV data and execute the SV transmission process. In the SV transmission process, the arithmetic processing unit 1431 instructs the transmission / reception circuit 1432 to transmit the SV data to the IED via the communication IF 16.

[0026] The MU1 also receives trip command information from the IED using a communication method called GOOSE (Generic Object Oriented Substation Event), which is specified in the international standard IEC61850. The arithmetic processing unit 1331 of MU1 processes the trip command information via GOOSE communication via the communication IF 15, and the arithmetic processing unit 1431 processes the trip command information via the communication IF 16. The arithmetic processing units 1331 and 1431 output a trip signal to operate the relays in the output board 12. The above describes the process in MU1 for acquiring the electrical quantity of the power system and transmitting it as SV data, and the process for outputting a trip command using GOOSE. Next, we will explain in detail the process for generating sampling timing using PTP.

[0027] FIG. 2 is a block diagram for explaining the sampling timing generation process in the transmission processing circuits 1332 and 1432 of the MU1. Master clock (1) and master clock (2) transmit PTP packets at specific intervals to the target slave device (slave clock). Here, transmission processing circuit 1332 of MU1 is provided as a slave clock for master clock (1), and transmission processing circuit 1432 is provided as a slave clock for master clock (2). MU1 receives a PTP packet from the master clock (1) at the PTP time synchronization control unit 13321 via the communication IF 15. The PTP time synchronization control unit 13321 synchronizes and corrects the clock counter based on the information in the received PTP packet. Then, based on the synchronized and corrected clock counter, a synchronization signal is sent to the A / D timing generation unit 13322, and the A / D synchronization counter is synchronized and corrected. Finally, the A / D timing generation unit 13322 sends sampling timing (1) to the A / D conversion unit 132, and based on this, first sampling synchronization is realized.

[0028] MU1 also receives a PTP packet from the master clock (2) at the PTP time synchronization control unit 14321 via the communication IF 16. The PTP time synchronization control unit 14321 synchronizes and corrects the clock counter based on the information in the received PTP packet. Furthermore, based on the synchronized and corrected clock counter, a synchronization signal is sent to the A / D timing generation unit 14322, and the A / D synchronization counter is synchronized and corrected. Finally, the A / D timing generation unit 14322 sends sampling timing (2) to the A / D conversion unit 142, and based on this, second sampling synchronization is realized.

[0029] [Configuration of protective relay system] FIG. 3 is a system configuration diagram showing an example of the configuration of a digital substation including a self-end substation and an opposing substation in the protective relay system of this embodiment. At the local substation, MU1, IED2 (main station) for IP-PCM current differential carrier protective relay, IED3 for on-site protective relay, and master clock device 4 (hereafter referred to as "MC4") are connected via a communication interface to a transmission path called process bus 5. IED2 for IP-PCM current differential carrier protective relay is an IED for inter-substation protective relay (intelligent electronic device for inter-substation protective relay).

[0030] At the opposite substation, MU1', IED2' (slave station) for IP-PCM current differential carrier protective relay, IED3' for on-site protective relay, and MC4' are connected to a transmission line called process bus 5' via a communication interface. The process bus 5 at the local substation and the process bus 5' at the opposite substation are connected to an IP-PCM communication network 6. Note that components indicated with symbols with a prime are the same as components indicated with symbols without a prime.

[0031] MU1 is connected to the process bus 5 via communication IFs 15 and 16, and MU1' is connected to the process bus 5' via communication IFs 15' and 16'. IP-PCM current differential carrier protective relay IED2 is connected to the process bus 5 via communication IF 22, and IP-PCM current differential carrier protective relay IED2' is connected to the process bus 5' via communication IF 15'. Premises protective relay IED3 is connected to the process bus 5 via communication IF 32, and premise protective relay IED3' is connected to the process bus 5' via communication IF 32'. MC4 is connected to the process bus 5 via communication IF 42, and MC4' is connected to the process bus 5' via communication IF 42'.

[0032] Since the process bus in this embodiment does not have a redundant configuration, the number of communication interfaces that each device has is one per processing board. In contrast, if the process bus has a redundant configuration (for example, if the PRP (Parallel Redundancy Protocol) method or the HSR (High-availability Seamless Redundancy) method defined in IEC 62439-3 is adopted), the number of communication interfaces that each device has is not limited to one.

[0033] The transmission path in this embodiment is configured to be logically divided using a network virtualization technology called VLAN (Virtual Local Area Network). In this configuration example, the transmission line is logically divided into three segments. The first segment is a transmission network consisting of communication IF15 of MU1, communication IF22 of IED2 (master station) for IP-PCM current differential carrier protection relay, communication IF15' of MU1', and communication IF22' of IED2' (slave station) for IP-PCM current differential carrier protection relay. The second segment is a transmission network made up of the communication IF 16 of MU1, the communication IF 32 of the IED 3 for the on-site protection relay, and the communication IF 42 of MC4. The third segment is a transmission network made up of a communication IF 16' of MU1', a communication IF 32' of the on-site protection relay IED 3', and a communication IF 42' of MC4'.

[0034] In this embodiment, the PTP synchronous network is divided into three using VLAN virtualization technology. In synchronous network (1), the operation board 21 (internal clock) of the IP-PCM current differential carrier protective relay IED2 (master station) serves as the master clock, and the operation board 21' of the IP-PCM current differential carrier protective relay IED2' (slave station), the operation board 13 of MU1, and the operation board 13' of MU1' serve as slave clocks. In this embodiment, the internal clock of IED2 is used as the master clock, but the internal clock of one of the other devices may also be used as the master clock. The operation board 13 of MU1 and the operation board 13' of MU1' generate sampling timing (1) based on synchronized time counters using the master clock of synchronous network (1).

[0035] In the synchronous network (2), the operation board 41 of MC4 serves as the master clock, and the operation board 31 of the IED3 for the on-site protection relay and the operation board 14 of MU1 serve as slave clocks. The operation board 14 of MU1 generates sampling timing (2) based on a time counter synchronized with the master clock of the synchronous network (2). In the synchronous network (3), the operation board 41' of MC4' serves as the master clock, and the operation board 31' of the on-site protection relay IED3' and the operation board 14' of MU1' serve as slave clocks. The operation board 14' of MU1' generates sampling timing (3) based on a time counter synchronized with the master clock of the synchronous network (3).

[0036] In this embodiment, the transmission line is logically divided into three segments, but it may be physically divided instead of being logically divided. For example, this embodiment can also be applied to a configuration in which the process bus 5 of the local substation, the IP-PCM communication network 6, and the process bus 5' of the opposite substation are disconnected. In this case, MU1 is connected to the IP-PCM communication network 6 via communication IF 15 and to the process bus 5 via communication IF 16, and MU1' is connected to the IP-PCM communication network 6 via communication IF 15' and to the process bus 5' via communication IF 16'.

[0037] Furthermore, the IP-PCM current differential carrier protective relay IED2 is connected to the IP-PCM communication network 6 via a communication IF22, and the IP-PCM current differential carrier protective relay IED2' is connected to the IP-PCM communication network 6 via a communication IF22'. Furthermore, the premise protective relay IED3 is connected to the process bus 5 via a communication IF32, and the premise protective relay IED3' is connected to the process bus 5' via a communication IF32'. Furthermore, the MC4 is connected to the process bus 5 via a communication IF42, and the MC4' is connected to the process bus 5' via a communication IF42'.

[0038] [Procedure for protection relay system] The processing procedure in this embodiment will be described below. The MU1 acquires electrical quantities (current and voltage) at its own substation. The calculation board 13 A / D converts the acquired electrical quantity signals at sampling timing (1) and transmits the A / D converted digital information as SV data to the IED2 (main station) for the IP-PCM current differential carrier protection relay. Furthermore, the arithmetic board 14 A / D converts the acquired electrical quantity signal at the sampling timing (2) and transmits the A / D converted digital information to the on-site protection relay IED 3 as SV data. The operation board 21 of the IED2 (main station) for the IP-PCM current differential carrier protection relay receives the SV data sent from the operation board 13 of the MU1, converts it into a specific communication format, and processes it to send it to the IED2' (slave station) for the IP-PCM current differential carrier protection relay.

[0039] MU1' acquires electrical quantities (current and voltage) at the opposite substation. Calculation board 13' A / D converts the acquired electrical quantity signals at sampling timing (1) and transmits the A / D converted digital information to IED2' (slave station) for IP-PCM current differential carrier protective relay as SV data. Calculation board 14' A / D converts the acquired electrical quantity signals at sampling timing (3) and transmits the A / D converted digital information to IED3' for on-site protective relay as SV data.

[0040] The operation board 21' of the IP-PCM current differential carrier protection relay IED2' (slave station) receives the SV data sent from the operation board 13' of the MU1', converts it into a specific communication format, and processes it to send it to the IP-PCM current differential carrier protection relay IED2 (master station).

[0041] The IP-PCM current differential carrier protective relay IED2 performs protective relay calculations based on the SV data transmitted from the operation board 13 of MU1 and the electrical quantity information of the data transmitted from the operation board 21' of the IP-PCM current differential carrier protective relay IED2' (slave station). Then, when the relay operation conditions are met, the IP-PCM current differential carrier protective relay IED2 transmits trip command information as GOOSE data to the operation board 13 of MU1.

[0042] The IP-PCM current differential carrier protective relay IED2' (slave station) performs protective relay calculations based on the SV data transmitted from the operation board 13' of the MU1' and the data electrical quantity information transmitted from the operation board 21 of the IP-PCM current differential carrier protective relay IED2 (master station). Then, when the relay operation conditions are met, the IP-PCM current differential carrier protective relay IED2' transmits trip command information as GOOSE data to the operation board 13' of the MU1'.

[0043] The IED3 for the on-site protection relay performs protection relay calculations based on the electrical quantity information of the SV data transmitted from the calculation board 14 of MU1, and if the relay operation conditions are met, it transmits trip command information to the calculation board 14 of MU1 as GOOSE data. The IED3' for the on-site protection relay performs protection relay calculations based on the electrical quantity information of the SV data transmitted from the calculation board 14' of the MU1', and if the relay operation conditions are met, it transmits trip command information as GOOSE data to the calculation board 14' of the MU1.

[0044] [Modification of the first embodiment] A modified example of the processing procedure in this embodiment will now be described. The MU1 acquires electrical quantities (current and voltage) at its own substation. The calculation board 13 A / D converts the acquired electrical quantity signals at sampling timing (1) and transmits the A / D converted digital information as SV data to the IP-PCM current differential carrier protective relay IED2 (master station) and the IP-PCM current differential carrier protective relay IED2' (slave station). Furthermore, the arithmetic board 14 A / D converts the acquired electrical quantity signal at the sampling timing (2) and transmits the A / D converted digital information to the on-site protection relay IED 3 as SV data.

[0045] The MU1' acquires electrical quantities (current and voltage) at the opposite substation. The calculation board 13' A / D converts the acquired electrical quantity signals at sampling timing (1) and transmits the A / D converted digital information as SV data to the IP-PCM current differential carrier protective relay IED2 (master station) and the IP-PCM current differential carrier protective relay IED2' (slave station). The calculation board 14' A / D converts the acquired electrical quantity signals at sampling timing (3) and transmits the A / D converted digital information as SV data to the on-site protective relay IED3'.

[0046] The IED2 for the IP-PCM current differential carrier protection relay performs protection relay calculations based on the electrical quantity information of the SV data sent from the calculation board 13 of MU1 and the calculation board 13' of MU1', and if the relay operation conditions are met, it sends trip command information to the calculation board 13 of MU1 as GOOSE data. The IED2' for the IP-PCM current differential carrier protection relay performs protection relay calculations based on the electrical quantity information of the SV data sent from the calculation board 13 of MU1 and the calculation board 13' of MU1', and if the relay operation conditions are met, it sends trip command information to the calculation board 13' of MU1' as GOOSE data.

[0047] The IED3 for the on-site protection relay performs protection relay calculations based on the electrical quantity information of the SV data transmitted from the calculation board 14 of MU1, and if the relay operation conditions are met, it transmits trip command information to the calculation board 14 of MU1 as GOOSE data. The IED3' for the on-site protection relay performs protection relay calculations based on the electrical quantity information of the SV data transmitted from the calculation board 14' of the MU1', and if the relay operation conditions are met, it transmits trip command information as GOOSE data to the calculation board 14' of the MU1. In this embodiment, only one MU1 is installed in each substation, but this is not a limitation and multiple MUs may be installed in a substation.

[0048] [Effects of the first embodiment] In this embodiment, a single input conversion board 11 and two operation boards 13 and 14 are mounted in a single MU1 unit, and the sampling timing of each operation board is synchronized to a different destination. As a result, the same analog signal is input to each operation board, but the sampling timing of the A / D conversion unit on each operation board is different, making it possible to realize a single MU.

[0049] Therefore, according to this embodiment, it is possible to support both the synchronization network (1) for performing inter-substation protection relay calculations and the synchronization network (2) (or synchronization network (3)) for performing substation premises protection relay calculations, so there is no need to double-take specific electrical quantity information from the master unit for each synchronization network. This means that the number of analog channels (or number of units) of the MU can be kept to the minimum required, which contributes to improved economy.

[0050] Furthermore, the MU1 is implemented with only a single output board 12, which has the advantage that the relay output circuit to the circuit breaker of the line processed by the MU1 can be shared. At the same time, because the synchronization networks for the inter-substation protection relays and the substation premises protection relays can be constructed separately, the extent of the impact on the entire protection relay system can be reduced compared to a full-system synchronization system spanning substations, even in the event of a time synchronization failure, for example, due to a master clock failure, thereby contributing to improved system reliability.

[0051] <Second embodiment> Next, a second embodiment of the present invention will be described with reference to Fig. 4. In Fig. 4, the same parts as those in Figs. 1 to 3 described in the first embodiment are given the same reference numerals, and duplicated explanations will be omitted. This embodiment is an example of an application to a conventional protection relay system (hereinafter referred to as a "legacy system") in which the local substation is a digitalized protection relay system, while the opposing substation is a non-digitalized conventional protection relay system. The configuration of the MU1 is the same as that of the MU1 described in the first embodiment (configuration shown in FIGS. 1 and 2), so a description thereof will be omitted.

[0052] [Configuration of protective relay system] As shown in Figure 4, the local substation has MU1, IED2 (main station) for IP-PCM current differential carrier protection relay, IED3 for on-site protection relay, and MC4, which are connected to the process bus 5 via a communication IF. The opposite substation is equipped with a legacy device 7 (slave station) for conventional IP-PCM current differential carrier protective relays. The process bus 5 of the local substation and the legacy device 7 (slave station) for IP-PCM current differential carrier protective relays of the opposite substation are connected to the IP-PCM communication network 6.

[0053] MU1 is connected to the process bus 5 via communication IFs 15 and 16. IED2 for IP-PCM current differential carrying protection relay is connected to the process bus 5 via communication IF 22. IED3 for premise protection relay is connected to the process bus 5 via communication IF 32. MC4 is connected to the process bus 5 via communication IF 42. Legacy device 7 is connected to the IP-PCM communication network 6 via communication IF 72.

[0054] In this embodiment, the process bus and IP-PCM communication network do not have a redundant configuration, so each device has one communication IF per processing board. However, if the process bus and IP-PCM communication network have a redundant configuration, the number of communication IFs each device has is not limited to one.

[0055] The transmission path in this embodiment is configured to be logically divided using a network virtualization technology called VLAN (Virtual Local Area Network). In this embodiment, the transmission line is logically divided into two segments. The first segment is a transmission network consisting of the communication IF15 of MU1, the communication IF22 of IED2 (main station) for IP-PCM current differential carrier protective relay, and the communication IF72' of legacy device 7 for IP-PCM current differential carrier protective relay. The second segment is a transmission network made up of the communication IF 16 of MU1, the communication IF 32 of the IED 3 for the on-site protection relay, and the communication IF 42 of MC4.

[0056] In this embodiment, VLAN virtualization technology is used to divide a PTP-based synchronization network into two. In synchronization network (1), the internal clock of the operation board 21 of the IP-PCM current differential carrier protective relay IED2 (main station) serves as the master clock, and the operation board 71 of the IP-PCM current differential carrier protective relay legacy device 7 (slave station) and the operation board 13 of the MU1 serve as slave clocks.

[0057] In this embodiment, the internal clock of IED2 is used as the master clock, but the internal clock of one of the other devices may be used as the master clock. The operation board 13 of MU1 and the operation board 71 of the legacy device 7 (slave station) for IP-PCM current differential carrier protection relay generate sampling timing (1) based on the synchronized time counters using the master clock of the synchronization network (1).

[0058] In the synchronization network (2), the operation board 41 of MC4 serves as the master clock, and the operation board 31 of the IED3 for the on-site protection relay and the operation board 14 of MU1 serve as slave clocks. The operation board 14 of MU1 generates sampling timing (2) based on a time counter synchronized with the master clock of the synchronization network (2).

[0059] Although this embodiment is configured to logically divide the transmission line into two segments, it is also applicable to a configuration in which the transmission line is physically divided. For example, in a configuration in which the transmission line is physically divided, the process bus 5 of the local substation is disconnected from the IP-PCM communication network 6, and MU1 is connected to the IP-PCM communication network 6 via communication IF 15 and to the process bus 5 via communication IF 16. Furthermore, the IED2 for the IP-PCM current differential carrier protective relay is connected to the IP-PCM communication network 6 via a communication IF22, and the legacy device 7 for the IP-PCM current differential carrier protective relay is connected to the IP-PCM communication network 6 via a communication IF72. Furthermore, the IED3 for the premises protective relay is connected to the process bus 5 via a communication IF32, and the MC4 is connected to the process bus 5 via a communication IF42.

[0060] [Procedure for protection relay system] The processing procedure in this embodiment will be described below. The MU1 acquires electrical quantities (current and voltage) at its own substation. The calculation board 13 A / D converts the acquired electrical quantity signals at sampling timing (1) and transmits the A / D converted digital information as SV data to the IED2 (main station) for the IP-PCM current differential carrier protection relay.

[0061] Furthermore, the arithmetic board 14 A / D converts the acquired electrical quantity signal at the sampling timing (2) and transmits the A / D converted digital information to the on-site protection relay IED 3 as SV data. The operation board 21 of the IED2 (main station) for IP-PCM current differential carrier protection relay receives the SV data sent from the operation board 13 of the MU1, converts it into a specific communication format used in conventional legacy systems, and transmits it to the legacy device 7 (slave station) for IP-PCM current differential carrier protection relay.

[0062] The legacy device 7 (slave station) for IP-PCM current differential carrier protective relay acquires electrical quantities (current and voltage) at the opposite substation. The calculation board 71 A / D converts the acquired electrical quantity signal at sampling timing (1) and transmits the A / D converted digital information to the IED2 (master station) for IP-PCM current differential carrier protective relay. Note that the legacy device 7 for IP-PCM current differential carrier protective relay does not support the IEC61850 communication method, and the communication method is equivalent to that of the conventional legacy system.

[0063] The IP-PCM current differential carrier protective relay IED2 performs protective relay calculations based on the electrical quantity information of the SV data sent from the operation board 13 of MU1 and the electrical quantity information sent from the operation board 71 of the IP-PCM current differential carrier protective relay legacy device 7 (slave station). Then, when the relay operation conditions are met, the IP-PCM current differential carrier protective relay IED2 sends trip command information to the operation board 13 of MU1 as GOOSE data. The data received by the IED2 (main station) for the IP-PCM current differential carrying protection relay is in a format conforming to IEC61850 and a format conforming to the conventional legacy system, but is converted into a common format by the calculation board 21 and then subjected to calculation processing.

[0064] The legacy device 7 for IP-PCM current differential carrier protective relay performs protective relay calculations based on the calculation board 21 of the IED2 (main station) for IP-PCM current differential carrier protective relay and the electrical quantity information measured within the device itself, and if the relay operation conditions are met, outputs a trip command to the main device of the opposing substation.

[0065] The IED3 for the on-site protection relay performs protection relay calculations based on the electrical quantity information of the SV data transmitted from the calculation board 14 of MU1, and if the relay operation conditions are met, it transmits trip command information to the calculation board 14 of MU1 as GOOSE data. In the example, only one MU1 is installed in the local substation, but this configuration is not limited to this and multiple MU1s may be installed in the substation.

[0066] [Effects of the second embodiment] Thus, according to this embodiment, the same effects as those of the first embodiment can be obtained. Furthermore, in the case of this embodiment, the IED2 has a compatibility processing function between a communication method conforming to IEC 61850 and a communication method conforming to a legacy system, so that even if the opposing substation uses a legacy system, it is possible to migrate the local substation to a digital substation all at once.

[0067] <Modification> It should be noted that the embodiments described so far have been described in detail to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. For example, in Figures 1 to 4, only control lines and information lines that are considered necessary for explanation are shown, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are interconnected. [Explanation of symbols]

[0068] 1, 1'...Merging Unit (MU) 2, 2'...IP - Intelligent Electronic Device (IED) for PCM Current Differential Carrying Protection Relays 3, 3'...Intelligent Electronic Device (IED) for Premises Protection Relay 4, 4'...Master clock device (MC) 5, 5'...Process bus 6...IP-PCM communication network, 7...IP - Legacy Device for PCM Current Differential Carrying Protection Relay 11...Input conversion board 12...Output board 13, 13', 14, 14', 21, 21', 31, 31', 41, 41', 71...Computation board 15, 15', 16, 16', 22, 22', 32, 32', 42, 42', 72...Communication IF 131, 141...Analog filters 132, 142...A / D conversion section 133, 143...Integrated circuit section 1331, 1431...Processing unit 1332, 1432...Transmission processing circuit 13321, 14321...PTP time synchronization control unit 13322, 14322...A / D timing generation section

Claims

1. A merging unit having an input conversion board that takes in analog information of a power system from a main unit, a first calculation board, and a second calculation board, The first computing board includes: a circuit unit that generates a first sampling timing; a first A / D conversion unit that converts an analog output signal of the input conversion board into a digital signal at the first sampling timing; a first transmitting unit that transmits the first digital data; The second computing board includes: a circuit unit that generates a second sampling timing; a second A / D conversion unit that converts an analog output signal of the input conversion board into a digital signal at the second sampling timing; a second transmitting unit that transmits the second digital data, the first sampling timing is time-synchronized with a first master clock; The second sampling timing is time-synchronized with a second master clock that is different from the first master clock. Merging unit.

2. the merging unit is connected to an inter-substation protection relay communication network with an opposite substation different from the local substation in which the merging unit is installed, the first master clock is implemented in a device connected to the inter-substation protection relay communication network; The second master clock is mounted on a device connected to a process bus in the local substation where the merging unit is installed. The merging unit according to claim 1 .

3. the merging unit is connected to an inter-substation protection relay communication network with an opposite substation different from the local substation in which the merging unit is installed, the first digital data is used for protection relay calculation between the substations, The second digital data is used for protection relay calculations within the premises of the local substation. The merging unit according to claim 1 .

4. An output board is provided, The output board is characterized in that it operates upon receiving trip command information resulting from either a protective relay calculation based on the first digital data or a protective relay calculation based on the second digital data. The merging unit according to claim 1 .

5. A protection relay system in which a self-end substation and an opposing substation are network-connected by a communication network for inter-substation protection relays, The local substation includes a first merging unit; a master clock device; An intelligent electronic device for inter-substation protection relays; an intelligent electronic device for a local substation premises protection relay; a second merging unit at the opposing substation; an intelligent electronic device for the inter-substation protection relay; The first merging unit and the second merging unit each have an input conversion board that takes in analog information of the power system from a main unit, a first calculation board, and a second calculation board; the first computing board comprises a circuit unit that generates a first sampling timing, a first A / D conversion unit that converts an analog output signal of the input conversion board into a digital signal at the first sampling timing, and a first transmission unit that transmits the first digital data to an intelligent electronic device for the inter-substation protection relay; the second computing board comprises a circuit unit for generating a second sampling timing, a second A / D conversion unit for converting an analog output signal of the input conversion board into a digital signal at the second sampling timing, and a second transmission unit for transmitting the second digital data to an intelligent electronic device for the substation premises protection relay; the first sampling timing is time-synchronized with a first master clock; The second sampling timing is time-synchronized with a second master clock. Protection relay system.

6. The first master clock is an internal clock of an intelligent electronic device for inter-substation protection relays connected to the inter-substation protection relay communication network of the local substation; The second master clock is an internal clock of the master clock device connected to the process bus of the local substation. The protective relay system according to claim 5.

7. The intelligent electronic device for inter-substation protection relay has a function of converting a format of the first digital data of the first merging unit or the second merging unit and transmitting the converted data to an intelligent electronic device for inter-substation protection relay installed in a different substation. The protective relay system according to claim 5.

8. The first master clock is an internal clock of an intelligent electronic device for inter-substation protection relays connected to the inter-substation protection relay communication network of the local substation; the second master clock is an internal clock of the master clock device connected to the process bus of the local substation; the intelligent electronic device for inter-substation protection relay has a function of converting a format of the first digital data of the merging unit and transmitting the converted data to an intelligent electronic device for inter-substation protection relay installed in a different substation; the intelligent electronic device for inter-substation protection relay installed at the local substation performs protection relay calculation using the first digital data of the first merging unit installed at the local substation and the digital data of the intelligent electronic device for inter-substation protection relay installed at the opposite substation; the intelligent electronic device for inter-substation protection relay installed in the opposite substation performs protection relay calculation using the digital data of the intelligent electronic device for inter-substation protection relay installed in the local substation and the first digital data of the second merging unit installed in the opposite substation; The intelligent electronic device for the substation premises protection relay installed at the local substation performs protection relay calculations using the second digital data of the first merging unit installed at the local substation. The protective relay system according to claim 5.

9. The first master clock is an internal clock of an intelligent electronic device for inter-substation protection relays connected to the inter-substation protection relay communication network of the local substation; the second master clock is an internal clock of the master clock device connected to the process bus of the local substation; the intelligent electronic device for inter-substation protection relay installed at the local substation performs protection relay calculation using the first digital data of the first merging unit installed at the local substation and the first digital data of the second merging unit installed at the opposite substation; the inter-substation protective relay intelligent electronic device installed in the opposite substation performs protective relay calculations using the first digital data of the first merging unit installed in the local substation and the first digital data of the second merging unit installed in the opposite substation; The intelligent electronic device for the substation premises protection relay installed at the local substation performs protection relay calculations using the second digital data of the first merging unit installed at the local substation. The protective relay system according to claim 5.

10. a synchronization network in the process bus of the substation at its own end and a synchronization network in the inter-substation protection relay communication network are separated from each other; The protective relay system according to claim 5.

11. A protection relay system in which a self-end substation and an opposing substation are network-connected by a communication network for inter-substation protection relays, The local substation comprises a merging unit, a master clock device; An intelligent electronic device for inter-substation protection relays; an intelligent electronic device for a substation premises protection relay; the opposing substation is equipped with a legacy device for inter-substation protection relay; The merging unit includes an input conversion board that receives analog information of the power system from the main unit, a first arithmetic board, and a second arithmetic board; the first computing board comprises a circuit unit for generating a first sampling timing, a first A / D conversion unit for converting an analog output signal of the input conversion board into a digital signal at the first sampling timing, and a first transmission unit for transmitting the first digital data to an intelligent electronic device for the inter-substation protection relay; the second computing board comprises a circuit unit for generating a second sampling timing, a second A / D conversion unit for converting an analog output signal of the input conversion board into a digital signal at the second sampling timing, and a second transmission unit for transmitting the second digital data to an intelligent electronic device for the substation premises protection relay; the first sampling timing is time-synchronized with a first master clock; The second sampling timing is time-synchronized with a second master clock. Protection relay system.

12. The first master clock is an internal clock of an intelligent electronic device for inter-substation protection relays connected to the inter-substation protection relay communication network of the local substation; The second master clock is an internal clock of the master clock device connected to the process bus of the local substation. The protective relay system according to claim 11.

13. The intelligent electronic device for the inter-substation protection relay installed at the local substation has a function of converting the format of the first digital data of the merging unit installed at the local substation and transmitting the converted data to the legacy device for the inter-substation protection relay at the opposite substation. The protective relay system according to claim 11.

14. The first master clock is an internal clock of an intelligent electronic device for inter-substation protection relays connected to the inter-substation protection relay communication network of the local substation; the second master clock is an internal clock of the master clock device connected to the process bus of the local substation; the intelligent electronic device for the inter-substation protection relay installed at the local substation has a function of converting a format of the first digital data of the merging unit installed at the local substation and transmitting the converted digital data to the legacy device for the inter-substation protection relay at the opposite substation; the intelligent electronic device for the inter-substation protective relay installed at the local substation performs a protective relay calculation using the first digital data of the merging unit installed at the local substation and digital data of the legacy device for the inter-substation protective relay installed at the opposite substation; The legacy inter-substation protective relay device installed at the opposite substation performs protective relay calculations using digital data from the intelligent electronic device for the inter-substation protective relay installed at the local substation and digital data measured within the legacy device itself; The intelligent electronic device for the substation premises protection relay installed at the local substation performs protection relay calculations using the second digital data of the merging unit installed at the local substation. The protective relay system according to claim 11.

15. a synchronization network in the process bus of the substation at its own end and a synchronization network in the inter-substation protection relay communication network are separated from each other; The protective relay system according to claim 11.

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