JP5530956B2 - Protective relay device using a transmission line - Google Patents

Description

  The present invention relates to a protective relay device that uses a transmission line, and more particularly, to a protective relay device that uses a transmission line suitable for transmission line addition accompanying terminal addition of a transmission line.

  There are various types of protective relay devices that use transmission lines, but current data is transmitted and received through the transmission line, and system faults in the protection section are detected to eliminate accidents. Electric devices are widely used. As a specific example, for example, a PCM current differential protection relay device described in Patent Document 1 or Non-Patent Document 1 is known. As a transmission method in this case, for example, a method of cyclically transmitting data at a predetermined cycle at a transmission rate of 54 kbps or 1.5 Mbps is adopted uniformly throughout the country, and the PCM current differential protection relay device It is applied as a mainstream configuration.

  This transmission method is based on the premise that it is configured on a dedicated network for power communication, and is configured by using a communication device such as a dedicated signal multiplexer (MUX).

  Naturally, networks and communication devices, which are communication infrastructures for electric power, are dedicated to electric power, introduced as special specifications, and contribute to stable power supply with high reliability and high availability.

Japanese Patent Application No. 2005-251100

Electric Cooperative Research Vol. 50 No. 1 2nd Generation Digital Relay

  Thus, the conventional protection relay device using a transmission line is configured using a power-dedicated communication network.

  However, on the other hand, the networks that make up the current social communication infrastructure are making great progress, such as responding to demands for higher speed, higher capacity, and drastic cost reduction. In the near future, it is expected that the technical gap between the dedicated power communication network communication infrastructure and the social communication infrastructure will further widen in the near future.

  Along with such progress, it is easily expected that the communication infrastructure devices that can be matched with the dedicated power communication network will be limited. In this case, if the communication infrastructure and communication equipment used in the protective relay device using the transmission path can be stably supplied in the future, the operational problem is small. However, as a practical matter, a stable supply in the future is not expected.

  For example, as a communication infrastructure used in a protection relay device that uses the current transmission path, a PDH (Plesiochronous Digital Hierarchy) or an SDH (Synchronous Digital Hierarchy) network However, in the future, it will become the mainstream to apply IP (Internet Protocol: Internet, LAN, etc.) network as a communication medium, and it is certain that this IP technology will be adopted for power communication. is there.

  With the progress of this network technology, the communication equipment side will be mainly product development toward the progress to the mainstream technology in the future, and this direction is fully expected to greatly accelerate in the future.

  In addition, there is no possibility (guarantee) that communication equipment manufacturers will continue to make equipment compatible with existing power communication networks in the future, and even if they are continuously supplied, the production volume is mainstream. Because it is extremely small compared to products, the product cost is considered to be significantly different from general-purpose products.

  In terms of operation, there is a concern that system operation costs will increase, including maintenance.

  For this reason, it is expected that a communication infrastructure based on the Ethernet (registered trademark) communication technology, which is a general-purpose technology, will be established in the future as a communication infrastructure for protection. It is a problem to make it easy to cope with the problem.

  In addition, it is expected that the need to seamlessly switch the system operation seamlessly will increase, and it goes without saying that this must be handled while maintaining the reliability level.

  The above issues have raised the problems that future trends related to communication infrastructure mainly give to protection relay devices that use transmission lines. On the other hand, transmission lines and power systems protected by protection relay devices It is also necessary to consider future trends on the side.

  On the power system side, with the diversification, it is considered that the number of transmission lines will increase, and in this case, as a protective relay device that uses transmission lines, transmission line terminals are added along with the addition of transmission line terminals. It is necessary to cope with the addition.

  From the above, in the present invention, protection relays using transmission lines that can cope with the development of communication infrastructure, can easily add transmission lines according to the addition of system terminals, and can expand the protection system configuration. An object is to provide an electric device.

The present invention solves the above-described problems, is provided at each terminal of an N-terminal power transmission line, takes in an analog AC electric quantity from the own-terminal transmission line, and uses an analog AC electric quantity taken in at the other end. The protection processing unit that gives an open command to the circuit breaker of the transmission line of the own terminal, and the analog AC electricity quantity of the own terminal are transmitted, and data is cyclically transmitted and received in order to receive the analog AC electricity quantity detected at the other terminal In the protective relay device using the transmission line including the first communication unit to perform,
The protection processing unit samples and inputs the analog AC electricity quantity at its own terminal, timing control means for determining the sampling timing, and shuts off the transmission line at its own terminal using the analog AC electricity quantity at its own terminal and the other end. A cyclic data transmission / reception using the first communication unit between the terminals of the N-terminal power transmission line with a calculation unit that gives an open command to the device and a second communication unit that performs packet communication,
When the (N + 1) th terminal is additionally installed in the N-terminal power transmission line, a means for sampling and inputting the analog AC electric quantity of the own terminal to the terminal, a timing control means for determining the sampling timing, the own terminal and the other end N terminal transmission line before adding a terminal by providing a protection processing unit including an arithmetic unit for giving an open command to the circuit breaker of the transmission line of its own terminal using an analog alternating current electric quantity and LAN communication means for performing packet communication While performing cyclic data transmission and reception using the first communication unit between each of the terminals,
Packet communication is executed between the second communication unit of the protection processing unit of an arbitrary terminal constituting each terminal of the N-terminal power transmission line before the terminal addition and the second communication unit of the protection processing unit of the additional terminal. .

  In addition, the sampling synchronization of each terminal after the terminal addition is performed based on the master clock of the main station, and the first communication unit that cyclically transmits and receives data and the second communication that performs additional packet communication Both parts are synchronized in sampling.

  The calculation unit of the protection processing unit includes a transmission / reception signal storage area used in the first communication unit and the second communication unit, and always performs a protection calculation using transmission / reception data written in the same area.

The present invention solves the above-described problems, is provided at each terminal of an N-terminal power transmission line, takes in an analog AC electric quantity from the power transmission line of its own terminal, and takes in an analog AC electric quantity taken in at the other end. A protection processing unit that gives an open command to the circuit breaker of the transmission line of the own terminal using a transmission control unit for transmitting the analog AC electric quantity of the own terminal and receiving the analog AC electric quantity detected by the counterpart terminal; In a protective relay device that uses a transmission line with a communication unit that cyclically transmits and receives data,
The protection processing unit samples and inputs the analog AC electricity quantity at its own terminal, timing control means for determining the sampling timing, and shuts off the transmission line at its own terminal using the analog AC electricity quantity at its own terminal and the other end. A calculation unit that gives an open command to the device, and a LAN communication means for performing packet communication,
The transmission control unit includes a transmission unit that transmits the analog AC electric quantity at its own terminal, a reception unit for receiving the analog AC electric quantity detected at the counterpart terminal, and supplying the analog AC electric quantity to the arithmetic processing unit of the protection processing unit. A sampling synchronization control means that obtains a sampling synchronization control signal from the received signal and gives it to the timing control means of the protection processing unit,
One of the timing control means is a master station that performs sampling at its own timing, and the timing control means of the other terminals are slave stations that execute sampling using a sampling synchronization control signal obtained from the received signal,
When the (N + 1) th terminal is additionally installed in the N-terminal power transmission line, a means for sampling and inputting the analog AC electric quantity of the own terminal to the terminal, a timing control means for determining the sampling timing, the own terminal and the other end A protection processing unit provided with a calculation unit that gives an open command to the circuit breaker of the power transmission line of its own terminal using an analog AC electric quantity of, and a LAN communication unit that performs packet communication,
Packet communication is performed between the LAN communication means of the protection processing unit of an arbitrary terminal and the LAN communication means of the protection processing unit of the additional terminal, and the protection processing unit of the additional terminal samples the signal received by the LAN communication means. A synchronization control signal is obtained and provided to the timing control means.

According to the protection control device of the present invention, when a terminal addition occurs when the existing protection network cannot be expanded, the protection system can be configured in the general-purpose network, so that the entire protection system is not stopped. Since the protection can be continued, the operating rate of the equipment can be increased.

  In addition, according to the embodiment of the present invention, it is possible to cope with the progress (migration) of the communication infrastructure without being subjected to conventional restrictions even in the facility update that is mainly performed on the communication device side. Since the network can be unified into a general-purpose network in the future, it can be unified from a special specification device to a general-purpose device, so that the equipment introduction cost and the operation cost can be suppressed.

The figure which shows the structure of the digital current differential protection relay apparatus using a transmission line. The figure which shows the transmission-and-reception part structure of a transmission control part route and a LAN communication control route. The figure which shows the example of a flame | frame at the time of the cyclic transmission by a transmission control part. The figure which shows the example of a format at the time of the packet communication by a LAN communication means. The figure which shows the sampling synchronization procedure at the time of cyclic transmission. The figure which shows the sampling synchronous procedure at the time of packet communication. The figure which shows the circuit example for simultaneous sampling of an analog signal. An analog / digital conversion operation explanatory drawing. FIG. 5 is a diagram illustrating a specific circuit example of the timing control unit 6. The figure which shows the timing correction operation example of an analog / digital conversion part. The figure which shows the characteristic of the operation area and non-operation area which are decided by the operation amount and the suppression amount. The figure which shows the characteristic of the operating area and non-operating area which are decided by inflow current and outflow current. Explanatory drawing which shows the additional expansion example of the protection relay apparatus accompanying terminal addition. Explanatory drawing which shows the additional expansion example of the protection relay apparatus accompanying terminal addition.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram showing an embodiment of a digital current differential protection relay device as an example of a protection relay device using a transmission line.

  In this figure, the transmission line to be protected was initially L1 only, and the A terminal and the B terminal were connected via the circuit breakers CBA and CBB and operated as a two-terminal system. Thereafter, the power transmission line L2 is added, and the C terminal is connected via the circuit breaker CBC to form a three-terminal system.

  In order to protect the power transmission line L1 from the beginning, protection processing units 100A and 100B, transmission control units 110A and 110B, and communication units 120A and 120B are installed at the A terminal and the B terminal. Here, both the transmission control unit 110 and the communication unit 120 are devices that constitute an existing conventional power-dedicated communication network, and perform so-called cyclic transmission.

  On the other hand, the protection processing unit 100C is installed at the C terminal added to the power transmission line. The protection processing unit 100 of each terminal basically has the same configuration. What is characteristic here is that the protection processing unit 100 includes a LAN communication unit and is cyclic with the protection processing unit 100C. The packet transmission started by sending is executed. That is, the protection processing unit 100 provided in common to each terminal can be connected to the transmission control unit 110 for signal transmission with the dedicated power communication network, and can perform cyclic transmission, and execute packet transmission. You can also. It enables communication between old and new.

  In FIG. 1, the B terminal protection processing unit 100B and the transmission control unit 110B are configured in the same manner as those of the A terminal, and therefore, the illustration of the inside is omitted here. Further, although signal transmission can be performed between the B terminal protection processing unit 100B and the C terminal protection processing unit 100C, illustration is omitted here.

  Hereinafter, the configuration and operation of each apparatus will be described. First, the protection processing unit 100 of each terminal converts the currents IA, IB, IC at the terminals and the voltages VA, VB, VC at the terminals into current transformers CTA, CTB, CTC, voltage transformation at each terminal. Input from devices PTA, PTB, PTC.

  The current and voltage signals are input to the analog signal input means 2 in the protection processing unit 100 and subjected to analog signal processing, and the analog / digital conversion means 3 converts the analog signal into a digital signal.

  Next, the calculation means 4 takes the input signal converted by the analog / digital conversion means 3 and performs various protection calculations, in particular, a differential calculation for obtaining a difference between the current signals, and makes an internal accident determination. When an internal accident is determined, a breaker trip command signal is output to the output means 5, and a trip command signal T is output from the output means 5 to the breaker CB.

  In general, this series of operations is repeated at every 30 ° electrical angle of the current signal of the transmission line, so that a system fault in the transmission line in the protection section is detected at high speed and the protection section is disconnected from the system. To make it work.

  The analog / digital conversion operation described above is started when the timing control means 6 (TIM control) gives a conversion command signal Sb to the analog / digital conversion means 3, and after a predetermined conversion time has elapsed, the digital data is converted into digital data. Converted.

  Although the self-terminal current, voltage input, and protection operation in the protection processing unit 100 are performed as described above, obtaining the current and voltage of other terminals necessary for executing the differential current calculation in the calculation means 4 This is performed using two communication methods having different methods. One of them uses an existing power dedicated communication network.

  In FIG. 1, a transmission control unit 110 that communicates system information such as voltage and current with a counterpart terminal is incorporated in an existing power dedicated communication network at existing A and B terminals. In the transmission control unit 110, 13 is a receiving means for receiving a signal from the other end, 12 is a transmitting means for transmitting a signal to the other end, 14 is a sampling control means (SPL means) for controlling a sampling synchronization signal, 11 Is a transmission control means for comprehensively controlling these transmission means, reception means and sampling synchronization control means, and 10 is a bidirectional access for transmission / reception of communication data (current data and control information) with the protection processing unit 100. Each of the possible memory means is configured to be tightly coupled to the protection processing unit 100 via a parallel bus.

  Transmission / reception data and information necessary for transmission control are configured to be transmitted via the memory means 10, and the sampling synchronization control means 14 sends a sampling synchronization control signal Sa for sampling synchronization control to the protection processing unit 100. Applied to the timing control means 6.

  Although the detailed operation will be described later, the timing control means 6 in the protection processing unit 100 causes the analog / digital conversion operation to be executed at a timing synchronized with the sampling synchronization control signal Sa.

  In order to synchronize sampling between a plurality of terminals and execute sampling at the same time, the sampling control is fixed at the main station (for example, the A terminal) serving as the clock master of the sampling synchronization signal and is dependent on the clock master. The slave terminal (slave station) synchronized with the signal performs sampling synchronization matching. In this way, by synchronizing all with the clock master of the main station, the operation is performed so as to match the sampling synchronization at all ends.

  In this way, the transmission control unit 110 is configured to perform processing in parallel with the protection processing unit 100, and is configured by applying, for example, a 1.544 Mbps cyclic transmission method.

  Transmission / reception signals from the transmission control unit 110 are generally connected to a power company's dedicated line, for example, a communication unit 120 represented by a 1.5M multiplexing station (MUX) for carrier relay devices. Then, it is transmitted as a signal multiplexed signal indicated by Se or Sf. Se is a downlink transmission signal when viewed from the A terminal, a downlink reception signal when viewed from the B terminal, and Sf is an uplink transmission signal when viewed from the B terminal and an uplink reception signal when viewed from the A terminal.

  In a transmission system using an existing dedicated power communication network, data transmission / reception can be performed between the A terminal and the B terminal by performing the cyclic transmission. The sampling synchronization control will be described later.

  The second communication method is packet communication using the LAN communication unit 7 of the protection processing unit 100. The protection processing unit 100 provided in common for each terminal includes the LAN communication means 7 as a standard. The LAN communication means 7 is connected to the transmission means 8 and the reception means 9 so as to transmit the transmission data Sg of the local end data and the transmission data Sh of the counterpart data in a packet communication transmission form. .

  In this case, as a matter of course, since real-time performance must be ensured, for example, the transmission mode is to be performed periodically (for example, every 15 ° or 30 ° electrical angle) in a simultaneous broadcast mode. Thus, synchronization control is executed for the transmission timing so that no timing conflict occurs.

  The data transmitted by the LAN communication means 7 is connected to the bus output from the calculation means 4 and transmitted in parallel. The sampling synchronization signal is operated upon receiving the sampling synchronization pulse Sc from the timing control means 6. Or you may start operation | movement by the transmission control from the calculating means 4 which operate | moves at the timing synchronized with the sampling synchronizing pulse Sc. Sd is a sampling synchronization signal reproduced from the received signal by the LAN communication means 7.

  However, as described above, the LAN communication unit 7 which is the second communication method of the A terminal and the B terminal is held as a device of the protection processing unit 100 in a state where it is operated as a two-terminal system. Is not used.

  In FIG. 1, the configuration of the protective relay device connected to the B terminal is exactly the same as that of the A terminal, and a description thereof is omitted here.

  Next, the configuration of the C terminal in FIG. 1 will be described. The protection processing unit 100 for the C terminal is an apparatus provided when the load end increases from the power transmission line L1 via L2.

  When adding a transmission device to the added C terminal, if it is possible to add a terminal of an existing protection dedicated network, a transmission device having the same configuration as the existing one is placed in the additional terminal (the same configuration as the A terminal is set). The protection system can be configured, but if the existing network becomes difficult to configure in the future, it is necessary to take additional terminal measures with a new method.

  Therefore, in the present invention, only the protection processing unit 100C provided with the LAN communication means is added, and the current differential protection relay system is constructed using the general-purpose network, so that the newly added branch load countermeasure can be easily realized. it can.

  The protection processing unit 100C provided with the LAN communication means has the same circuit configuration as the protection processing units 100a and 100b of FIG. 1, but does not have the transmission control unit 110, and is based on the Ethernet communication technology. Only a general-purpose optical fiber network is applied. That is, the configuration does not use an existing protection communication infrastructure dedicated to electric power.

  The present embodiment is characterized in that the transmission control route includes both a dedicated power route via the transmission control unit 110 and a general-purpose route via the LAN communication control.

  The above-described switching of both transmission routes is configured to be switched by a selection means (not shown) in the protection processing unit 100, and signals in each transmission route are selected according to the network operation status. To be configured.

  The major difference between the two transmission routes is that the transmission control unit 110 is cyclically controlled, whereas the LAN communication means is cyclically started to transmit packets.

  FIG. 2 is a diagram for explaining the configuration of the route through the transmission control unit 110 and the data transmission / reception unit of the route through the LAN communication control. Since this figure schematically shows the configuration of each data transmission / reception unit in the A terminal, there are portions that do not necessarily match the configuration of FIG. 1, but simply, the protection application means 2a and the transmission / reception data buffer means 2b. 1 is configured in the arithmetic unit 4 of FIG. 1, the data buffer unit 2f is configured in the transmission control unit 11 of the transmission control unit 110, and the cyclic data transfer unit 2g is configured in the communication unit 120 for transmission / reception. It should be understood that the data buffer means 2h is configured in the LAN communication means 7.

  According to this configuration, the transmission / reception data buffer means 2b, 2f, and 2g temporarily store transmission information and reception information, respectively, and the information on the A terminal is directed to the B terminal and the C terminal using the transmission signal line 2c. Is transmitted to the transmission part of the transmission / reception data buffer means 2f, 2g, and information on the B terminal and the C terminal is transmitted to the reception part of the transmission / reception data buffer means 2b for the A terminal using the reception signal lines 2d, 2e. . Thereby, sharing of information of each terminal is achieved.

  It should be noted that Ia, Ib, and Ic described in the transmission / reception data buffer means are currents of respective phases a, b, and c detected at the respective terminals, and ON / OFF is control information of the circuit breaker CB of each terminal, These are transmitted and received between the terminals.

  Hereinafter, the operation of FIG. 2 will be described using the A terminal device as an example. First, in the protection application means 2a of the A terminal, various protection operations (for example, protection relay device: 87) are performed, but the analog input information captured at the own terminal (A terminal) is transmitted to the transmission / reception data buffer means 2b. Write in the transmission part.

  The contents of data to be written are, for example, current input information Ia, Ib, Ic, bit information about breaker control information (ON / OFF), and the like. Thereafter, the data written in the transmission part of the transmission / reception data buffer means 2b is transferred to the transmission part of the transmission / reception data buffer means 2f in the transmission control means 11 of the transmission control section 110 via the transmission signal line 2c, and is transmitted. Copy the data as At the same time, the same data as described above is also copied to the transmission portion of the transmission / reception data buffer means 2h of the LAN communication means 7.

  Thereafter, the information written in the transmission part of the transmission / reception data buffer means 2f of the transmission control unit 110 is cyclically read out by the cyclic data transfer means 2g. For example (although the detailed description is omitted) It operates to send data to the B terminal according to a typical 1.5 Mbps transmission procedure.

  Further, in the LAN communication means 7, the information written in the transmission part of the transmission / reception data buffer means 2h is transmitted by the LAN transmission means 8 to the C terminal in the form of packet communication.

  Next, the reception operation will be described. First, the cyclic data transfer means 2g on the transmission control unit 110 side of the A terminal receives current information and other information from the other end (B terminal). After performing the synchronization processing, the received data is stored in the receiving portion of the transmission / reception data buffer means 2f. Thereafter, the reception data stored in the reception portion of the transmission / reception data buffer means 2f is transferred to and stored in the reception portion 1 of the transmission / reception data data buffer means 2b via the reception signal line 2d.

  Similarly, on the LAN communication means 7 side of the A terminal, the current information and other information from the other end (C terminal) received by the LAN receiving means 9 is stored in the receiving portion of the transmission / reception data buffer means 2h, and thereafter The received data is transferred and stored in the receiving portion 2 of the transmission / reception data buffer means 2b via the receiving signal line 2e.

  In the protection application 2a, a predetermined differential protection calculation is performed by using the local station data and the partner end data obtained as described above, and a system fault determination is performed.

  The configuration of FIG. 2 shows the configuration of each data transmission / reception unit in the A terminal when the transmission line is added from the 2 terminal to the 3 terminal. Circuits and communication functions are not used. Further, the configuration of each data transmission / reception unit in the B terminal may be considered that the configuration of FIG. 2 is installed in the B terminal as it is. However, the device provided in the C terminal does not include the transmission control unit 11 and the communication unit 120, and is configured to communicate with other terminals using the LAN communication unit 7. Therefore, when communicating with the A and B terminals, two sets of devices (transmission / reception data buffer means 2h, LAN transmission means 8, and LAN reception means 9) on the LAN communication means 7 side are provided.

  FIG. 3 shows an example of the format of data passing through the transmission control unit 110 and the LAN communication means 7 described above.

  Among these, FIG. 3A shows an example of a frame when cyclic transmission is performed on the transmission control unit 110 side. In cyclic transmission, current data (Ia, Ib, Ic) for three phases, ON / OFF information, subcome data, and CRC information are transmitted / received every period T (generally an electrical angle of 30 °). In the example of FIG. 3a, twelve subframes from F # 0 to F # 11 are configured within a period of period T, and the remaining subframes are used for transmission of voltage signals or currents and voltages of other lines. Or, it is used for transmission of phase signals and line signals. Since this frame describes a general configuration, detailed description thereof is omitted here.

  FIG. 3 b shows an example format for transmission / reception by packet communication of the LAN communication means 7. In this case, the beginning of the packet starts with a preamble, and destination address (DA), source address (SA), tag information (Tag), PDU, data (current data, ON / OFF information, status), frame check sequence (FCS). This packet is also configured from the preamble to the next preamble so as to be able to ensure real-time performance by repeating every period T. The data portion can also be used for transmission of a voltage signal, or a current, voltage, phase signal, or line signal of another line, as in FIG. 3a.

  Both the above transmission formats are transmitted / received at every electrical angle of 30 °, for example, and current information (Ia, Ib, Ic) and ON / OFF information necessary for the protection application 2a are added to existing routes and terminals. You can send and receive from the route.

  The point is that even if the communication infrastructure advances and only the packet communication network continues to exist in the future, it is meaningful to support a new general-purpose network while maintaining the existing protection application. In addition, it is also possible to execute protection calculations using information on additional terminals by receiving the voltage, current, and device information of the system with additional terminals via a general-purpose network and mounting it in an empty area of the existing network. .

  That is, a protection application using not only the current of the additional terminal but also the voltage information can be additionally constructed. Of course, if there is a vacant area in the transmission / reception transmission area, it can be constructed without affecting the existing network interface.

  FIG. 4 shows an outline of the operation of the two methods for achieving sampling synchronization between the master station (A terminal) and slave station (B terminal) of the current differential relay device described above. Only the points will be described below.

FIG. 4a shows an overview of the current sampling synchronization control.
(1) First, the slave station transmits a synchronization signal 4a to the master station.
(2) Next, the master station obtains a time difference TM from the timing of receiving the synchronization signal 4a from the slave station from the sampling timing (period ΔT1) of the own station.
(3) Subsequently, the master station transmits 4b the time difference TM obtained above to the slave station.
(4) The slave station obtains the time difference TS from the timing of receiving the synchronization signal transmitted from the master station from the sampling timing (cycle ΔT2) of the own station, and simultaneously reads the sampling time difference data TM received from the master station.
(5) Assuming that the delay time Tdu of data transmitted from the slave station to the master station is equal to the delay time Tdd of data transmitted from the master station to the slave station, the timing difference ΔT between the two is obtained by equation (1).
[Equation 1]
ΔT = (TS TM) / 2 (1)

(6) The slave station controls the sampling timing so that ΔT in the above equation becomes zero. The main station does not control.

  By repeating the above sampling synchronization control, the sampling timing of the master station and the slave station can be made substantially the same.

  Next, the second sampling synchronization method will be described with reference to FIG. FIG. 4b describes the sampling synchronization of the two-terminal configuration of the master station and the slave station.

This synchronization method is a method defined in IEEE 1588, and the method itself is not the subject of the invention of the present invention, and it is meaningful only to apply this method to a current differential relay device. For the explanation, only an outline is given.
(1) The master station transmits a transmission packet (SYNC) indicated by 4c for synchronous control to the slave station.
(2) Subsequently, the master station transmits the time data t1 at which the SYNC signal 4c is transmitted to the slave station in the next transmission packet (Follow W UP) indicated by 4d.
(3) The slave station takes out the time t0 at which the first transmission packet (SYNC) 4c is received and the transmission time data t1 in the transmission packet (FolloW UP) indicated by 4d.
(4) Further, the slave station transmits a transmission packet (DELAY REQUEST) indicated by 4e for synchronous control with respect to the master station. At this time, the slave station acquires the transmission time t2.
(5) The master station transmits the time t3 at which the packet 4e (DELAY REQUEST) is received on the next packet (DELAY RESPONSE) 4f to the slave station.
(6) The slave station acquires time t3 from the packet (DELAY RESPONSE) 4f.

Through these series of operations, the slave station can acquire time data of t0 to t3, and from this time data, the sampling timing between the master station and the slave station is calculated by the calculation shown in the following equations (2) and (3). The delay time tdx and the offset time toff, which are data for correcting the deviation, can be obtained.
[Equation 2]
tdx = ((t1-t0) + (t3-t2)) / 2 (2)
[Equation 3]
toff = (t2-t1) -tdx (3)

From the above equations (2) and (3), the slave station can be controlled so that the sampling time is the same as that of the master station by controlling toff to be close to zero.

  In this way, it is possible to send and receive packets that periodically measure the delay time of communication, but sampling synchronization control is possible even if it is performed irregularly.

  Needless to say, regarding the state of sampling synchronous control, it is necessary to constantly monitor the above-mentioned toff. For example, it is necessary to grasp the influence on the current differential calculation by monitoring that this offset is 1 μs or less. Lock the device.

  The transmission of current data is performed by packet transfer different from the above-described sampling synchronization control.

  FIG. 5 shows an example of a circuit for sampling an analog signal at the same time based on the synchronization timing extracted in FIG.

  In FIG. 5, reference numeral 2 denotes a circuit example of the analog input means of FIG. 1, and includes an input converter 5a for converting an analog input signal Si such as current and voltage into a voltage and an analog filter. The analog filter includes an operational amplifier 5d, a resistor 5b, and a capacitor 5c.

  The output 6 a of the analog input means 2 is applied to the analog / digital conversion circuit unit 3. Specifically, the analog filter output 6a is input to the sample and hold amplifier circuit 5e (S / H). The S / H circuit 5e samples the analog signal 6a according to a sampling command signal from the analog / digital control circuit 5i.

  This sampling command signal is used to set the sampling time to the same time at all terminals based on the synchronization signal Sb from the outside.

  The signal 6b sampled / held by the S / H circuit 5e is applied to the successive approximation circuit 5g (SAR). The successive approximation circuit 5g sequentially compares the input signal with the reference voltage source 5f (REF) in accordance with the control signal from the analog / digital control unit 5i. The result is an analog / digital conversion code that is output to the output driver 5j (OUTPUT DRV) and operates so that the conversion code is output to the outside.

  As a matter of course, this circuit is provided with a clock transmission means 5h (CLK) because it cannot operate sequentially without the clock transmission means. In the protective relay system, the above-described operation is repeatedly executed at a predetermined cycle.

  FIG. 6 shows a timing example of the conversion operation example of the analog signal shown in FIG. 5 into a digital signal. The operation will be described below with reference to FIG.

  The analog signal 6a is converted into an S / H waveform 6b in the S / H circuit 5e, and operates so as to perform analog / digital conversion during the holding period of the waveform.

  Sb is an analog / digital conversion command synchronization signal (CONVERT), and the analog / digital conversion operation is started when this signal becomes “L”. During analog / digital conversion, the status is displayed with the status shown in 6c. Specifically, when the status 6c becomes “L”, it has a function of notifying the outside (for example, a microcontroller, etc.) that it is in the “Busy state” meaning that conversion is in progress.

  6d shows the internal operation state, and shows how analog / digital conversion is performed in synchronization with the conversion timing in accordance with the timing when the analog / digital conversion command synchronization signal (CONVERT) Sb becomes “L”. Yes.

  6e shows an example of timing to the output register 5j of the analog / digital converter 3, and the conversion data is determined when the "Busy state" indicating that conversion is in progress at the timing 6c returns from L to H. To work.

  What is important here is that the analog / digital conversion command synchronization signal CONVERT is synchronized with the start point of the analog / digital conversion command synchronization signal CONVERT by the external synchronization signal Sb. That is, analog / digital conversion is possible.

  Needless to say, the analog / digital conversion command synchronization signal (CONVERT) Sb is determined based on the timing difference ΔT in the equation (1) described in FIG. 4 or the offset time toff in the equation (3). Absent. All terminals synchronous sampling is performed by obtaining ΔT or offset time toff on the subordinate terminal side and adjusting the sampling timing so that this value becomes zero.

  FIG. 7 shows a specific circuit example of the timing control means 6 of FIG. In FIG. 7, the selection circuit 7 c selects the synchronization signal Sa from the transmission control unit 110 and the synchronization signal Sd from the LAN communication unit 7 shown in FIG. 1. First, the rising edges of the synchronization signals Sa and Sd are detected by the individual detection circuit 7a, the pulse signal is generated by the timing pulse generation circuit 7b, and the pulse signal is applied to the selection circuit 7c.

  In the selection circuit 7c, the pulse signal 70b synchronized with the synchronization signal Sa or Sb is applied to the clear terminals of the two sets of counter circuits 7d and 7e to synchronize the counting operation.

  The counter circuits 7d and 7e perform a count-up operation based on the clock signal of the transmitter 7f (CLK), but clear the count value to 0 with the counter clear signal 70b and operate so as to start the count operation again. Synchronize.

  An output signal of this counter is applied to the combinational circuit 7g (COMB) to generate an analog / digital conversion command signal (CONVERT) Sb.

  What is important here is that the analog / digital conversion command synchronization signal (CONVERT) Sb operates to synchronize at the rising edge of the external synchronization signal Sa or Sd. That is, it operates so as to match the timing of the start of analog / digital conversion depending on the external synchronization signal.

  Here, at the terminal serving as the master station, the own station becomes the master clock, and the start timing of the analog / digital conversion timing is fixed, so that the timing control of the slave station that must be subordinately synchronized is an object.

  FIG. 8 shows an example of analog / digital conversion timing in which sampling of each terminal is synchronized.

  In FIG. 8, timing examples at the A terminal as the master station, the B terminal at the slave station, and the C terminal with the additional terminals are shown from the top.

  Since the A terminal is the main station, the synchronization signal Sa becomes the master clock, so the analog / digital conversion timing Sb of the cycle T2 is set at the timing synchronized with the rising edge of the master clock Sa of the cycle T1 (for example, electrical angle 30 °). Is generated. The synchronization signal Sa is a signal having a fundamental frequency oscillated by the sampling synchronization control means 14 of the transmission control unit 110 of the A terminal in FIG.

  The B terminal of the slave station receives the master clock Sa of the A terminal, generates a slave clock Sa of the B terminal synchronized with the master clock Sa, and generates an analog / digital conversion timing Sb with a period T2 at a timing synchronized with the rising edge. ing.

  The C terminal with an additional terminal operates as a slave station of the master station in terms of system. Therefore, since there is no existing transmission control means 110, the analog / digital conversion timing Sb of the period T2 is generated at a timing synchronized with the rise of the slave clock Sd from the LAN of the general-purpose network interface. The slave clock Sd from the LAN is a signal created from the received signal at the A terminal in the LAN communication means 7 at the C terminal, and is determined based on the offset time toff in the equation (3).

  In this way, the B terminal and the C terminal are synchronized with the A terminal by sampling synchronization, so that all-end sampling synchronization can be performed. Specifically, when the third C terminal is connected to the two-terminal system, the protection processing unit 100 is newly installed to apply the input of the C terminal, and the LAN communication means 7 is connected to connect the slave clock Sd from the LAN. In order to obtain the above, the selection circuit 7C in FIG. 7 may be set to select the signal Sd.

  FIG. 9 shows an example of operating characteristics of the current differential relay device constructed on the assumption that the sampling synchronization as described above is performed. FIG. 9a shows the characteristics of the operating region and the non-operating region determined by the operation amount Id on the vertical axis and the suppression amount ΣI on the horizontal axis. FIG. 9b shows the characteristics of the operating region and the non-operating region determined by the inflow current on the horizontal axis and the outflow current on the vertical axis. Since this characteristic itself is not different from the protection method of the conventional PCM digital current differential relay device, detailed description thereof will be omitted here.

  FIG. 10 is an explanatory diagram showing an example of additional expansion of the protective relay device accompanying terminal addition. In FIG. 10, conventionally, it was comprised with the 4-terminal power transmission line, and 10a, 10b, 10c, 10d was installed in each terminal as the protective relay device. In addition, a current differential protection system is configured by applying loop transmission using a power dedicated communication path of 1.544 Mbps for signal transmission between them.

  In this case, power transmission lines L1 and L2 were additionally installed, and protective relay devices 10e and 10f were added correspondingly. In the case of such an additional configuration, the protection relay devices 10e and 10f of the additional terminals establish the LAN communication path of FIG. 1 with the protection relay devices 10a and 10c of the nearest terminals. After the establishment of the LAN communication path, detection signals at all terminals are applied to the loop transmission path using the conventional power dedicated communication path and the additional LAN communication path, and each terminal current is shared.

  In addition, it is necessary to provide the necessary transmission / reception data buffer means in the protection processing unit 100 of the protective relay device when the LAN communication path is established, but by providing the transmission / reception data buffer means 2b and 2h of FIG. 2 in advance, Terminals can be easily added without special modification. In other words, the buffer circuit for three terminals in FIG. 2 may be prepared as standard from the beginning of the two-terminal configuration, and the protective relay device only needs to execute the three-terminal operation using the signals of all the buffers. Since the signal at the C terminal is zero, the differential operation is not affected. When the LAN communication path is established, the transition can be smoothly executed by inputting a significant signal. The general-purpose network of the present invention can be configured to be extended by transmitting and receiving the current and device information of the additional terminal.

  Currently, the maximum number of terminals is 8 to 16 terminals, but it is possible to cope with the case where the number of terminals exceeds this. Further, the terminals other than the additional terminals are protected as they are, and only the terminals 10a and 10c having the additional terminals can be added to the A 'and C' terminals. As a matter of course, by configuring with a general-purpose network interface, a flexible response independent of the existing network becomes possible.

  FIG. 11 shows a configuration of a case in which a plurality of additional terminals (A ′, A ″, A ″ ″ terminals) indicated by 10 g to 10 i are added to the A terminal. This case can also be handled in the same manner as in FIG.

  Both the cases of FIGS. 10 and 11 are solutions in the case where there is a limitation in the existing protection network, and it is assumed that a general-purpose network will be introduced in the system protection field in the future. It is important to have a network function.

  This configuration example in the general-purpose network has been described by taking an example of a direct optical connection state. For example, it is possible to construct a system even by applying an unused optical fiber, so that a network configuration can be made at low cost. Not to mention, it is possible to improve the economic efficiency, and it is possible to reduce the equipment introduction cost and the operation cost.

  In addition, since a general-purpose product can be applied to a communication device such as an optical module because a general-purpose network interface is applied, it goes without saying that future maintenance is superior to the current situation. That is, it can contribute to the stable supply of electric power.

L1, L2 ... Protection target transmission line CB ... Breaker CT ... Current transformer PT ... Voltage transformer 2 ... Analog input means 3 ... Analog / digital conversion means 4 ... Calculation means 5 ... Output means 6 ... Timing control means 7 ... LAN Communication means 8 ... LAN transmission means 9 ... LAN reception means 10 ... Transmission memory means 11 ... Transmission control means 12 ... Transmission control section transmission means 13 ... Transmission control section reception means 14 ... Sampling synchronization control means DESCRIPTION OF SYMBOLS 120 ... Communication part 100 ... Protection processing part 110 ... Transmission control part Sa ... Sampling synchronous signal Sb ... Analog / digital conversion command signal Sc ... Sampling synchronous signal Sd ... Sampling synchronous signal Se ... Reception signal Sf of B terminal ... Reception of A terminal Signal Sg ... Received signal at C terminal Sh ... Received signal at A terminal I ... Current signal taken from CT ... Taken from PT Voltage signal T: Breaking signal 2a for the circuit breaker: Protection application means 2b ... Transmission / reception data buffer means 2c ... Transmission signal line 2d, 2e ... Reception signal line 2f ... Data buffer means 2g of transmission control unit ... Cyclic data transfer means 2h ... Transmission / reception data buffer means 4a ... Transmission signal 4b from slave station to master station in transmission control ... Transmission signal 4c from master station to slave station in transmission control ... Synchronization start signal 4d from master station to slave station in LAN communication means ... LAN communication means Follow-up signal 4e from the master station to the slave station in the LAN. Delay information transmission request signal 4f from the slave station to the master station in the LAN communication means ... Delay information response signal 5a from the slave station to the master station in the LAN communication means ... Input converter 5b ... Resistor 5c ... Capacitor 5d ... Operational amplifier 5e ... Sample hold amplifier 5 ... Analog / digital conversion reference signal source 5g ... Successive comparison circuit 5h ... Analog / digital converter CLK generator 5i ... Analog / digital control circuit 5j ... Output driver circuit 6a ... Analog input signal waveform example 6b ... Sample hold waveform example 6c ... Analog / digital conversion operation status signal example 6d ... Analog / digital conversion operation example 6e ... Analog / digital converter output data example 7a ... Edge detection circuit 7b ... Pulse generation circuit 7c ... Selection circuits 7d, 7e ... Synchronization counter 7g ... Combination Circuit 7f ... CLK generation circuit 70b ... Counter clear signal

Claims (4)

It is provided at each terminal of the N-terminal power transmission line, takes in the analog AC electricity quantity from the power transmission line of its own terminal, and gives an open command to the circuit breaker of the power transmission line of its own terminal using the analog AC electricity quantity taken in at the other end A transmission line including a protection processing unit and a first communication unit that cyclically transmits and receives data in order to transmit the analog AC electric quantity of the terminal itself and receive the analog AC electric quantity detected by the counterpart terminal is used. In protective relay device,
The protection processing unit includes a means for sampling and inputting the analog AC electricity quantity of the own terminal, a timing control means for determining the timing of sampling, and an analog AC electricity quantity of the own terminal and the other end of the transmission line of the own terminal. A cyclic data transmission / reception using the first communication unit is performed between the terminals of the N-terminal power transmission line with a calculation unit that gives an open command to the circuit breaker and a second communication unit that performs packet communication,
When the (N + 1) th terminal is additionally installed in the N terminal transmission line, a sampling input means for the analog AC electric quantity of the own terminal, a timing control means for determining the sampling timing, and the own terminal and the counterpart. A protection processing unit including an arithmetic unit for giving an open command to the circuit breaker of the power transmission line of the terminal using the analog AC electric quantity at the end and a LAN communication means for performing packet communication is provided to transmit the N terminal before adding the terminal. While performing cyclic data transmission and reception using the first communication unit between the terminals of the electric wire,
Packet communication is executed between the second communication unit of the protection processing unit of any terminal constituting each terminal of the N-terminal power transmission line before the terminal addition and the LAN communication means of the protection processing unit of the additional terminal A protective relay device using a transmission line characterized by that. In the protective relay device using the transmission line according to claim 1 ,
Sampling synchronization of each terminal after the terminal addition is performed based on the master clock of the master station, and both the first communication unit that cyclically transmits and receives data and the second communication unit that performs additional packet communication A protective relay device using a transmission line characterized by sampling synchronization. In the protective relay device using the transmission line according to claim 1 or claim 2,
The calculation unit of the protection processing unit includes a transmission / reception signal storage area used in the first communication unit and the second communication unit, and always performs a protection calculation using transmission / reception data written in the same area. A protective relay device that uses the characteristic transmission line. Provided at each terminal of the N-terminal power transmission line, taking in the analog AC electricity from the self-terminal power transmission line and using the analog AC electricity captured at the other end to open the circuit breaker of the self-terminal power transmission line A protection processing unit for transmitting the analog AC electric quantity at the terminal, a transmission control unit for receiving the analog AC electric quantity detected at the other terminal, and a communication unit for cyclically transmitting and receiving data In protective relay devices that use transmission lines,
The protection processing unit includes a means for sampling and inputting the analog AC electricity quantity of the own terminal, a timing control means for determining the timing of sampling, and an analog AC electricity quantity of the own terminal and the other end of the transmission line of the own terminal. A calculation unit that gives an open command to the circuit breaker, and LAN communication means for performing packet communication,
The transmission control unit includes a transmission unit that transmits an analog AC electric quantity at its own terminal, a reception unit for receiving the analog AC electric quantity detected at the counterpart terminal, and providing the analog AC electric quantity detected by the counterpart terminal; and the reception unit A sampling synchronization control means that obtains a sampling synchronization control signal from the signal received at and gives to the timing control means of the protection processing unit,
One of the timing control means is a master station that performs sampling at its own timing, and the timing control means of the other terminal is a slave station that performs sampling using a sampling synchronization control signal obtained from the received signal,
When the (N + 1) th terminal is additionally installed in the N terminal transmission line, a sampling input means for the analog AC electric quantity of the own terminal, a timing control means for determining the sampling timing, and the own terminal and the counterpart. Provide a protection processing unit including an arithmetic unit that gives an open command to the circuit breaker of the power transmission line of the terminal using analog AC electricity at the end, and a LAN communication unit that performs packet communication,
Packet communication is performed between the LAN communication unit of the protection processing unit of an arbitrary terminal and the LAN communication unit of the protection processing unit of an additional terminal, and the protection processing unit of the additional terminal receives the LAN communication unit. A protection relay device using a transmission line, characterized in that a sampling synchronization control signal is obtained from a signal and applied to the timing control means.

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