JP2013031306A - Digital protection relay device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow data transmitted from an own-end device to an other-end device when a packet is transmitted to be effective and to be optimized.SOLUTION: An analog processing section 15 of the own-end device samples quantity of electricity obtained from a power system at a predetermined sampling period and converts the quantity of electricity to predetermined digital data for each sampling period. A data transmitting section 16 converts the predetermined digital data to a predetermined transmission format. A transmission timing controlling section 17 extracts the predetermined digital data of one sampling of the predetermined transmission format from the data transmitting section 16 N times within a prescribed time. A transmitting section 18 transmits N pieces of extracted digital data to the other-end device. A transmission receiving section 19 receives data transmitted from the other-end device. An arithmetic processing section 20 combines the data from the other-end device received by the transmission receiving section 19 with the digital data obtained by the analog processing section 15 and performs a relay calculation.

Description

  Embodiments described herein relate generally to a digital protection relay device that protects a power system.

  The power system protection relay device maintains the stable operation of the power system by removing the faulty section by controlling the circuit breaker when the amount of electricity exceeds the specified range due to a power system accident, etc. It is for making it happen.

  In a digital protection relay device that protects the power system, for example, in a device represented by a current differential protection relay device that protects a transmission line, current data synchronized between the devices is mutually exchanged. Send and receive and protect. This current data is communicated using a transmission rate of 54 kbps, 64 kbps, or 1.5 Mbps in order to satisfy requests from the protective relay device such as synchronization between data and operation time (for example, non-patent literature). 1).

  The current data is sampled at an electrical angle of 30 ° based on a signal inside the protective relay device, and then converted into a 12-bit digital signal and transmitted. Recently, an electrical angle of 3.75 ° is used. After being sampled, the data is processed into data having an electrical angle of 30 °, converted into a 12-bit digital signal, and transmitted (see Patent Document 1).

  FIG. 15 is an explanatory diagram of an example of a transmission format of a conventional current differential protection relay device. FIG. 15 shows a transmission format used for transmission at 54 kbps in a power system with a system frequency of 50 Hz. This is an example in which one sampling data of three current phases is transmitted in 90 bits.

  In recent years, the development of communication technology has enabled high-speed transmission with little transmission delay time and time fluctuation as typified by Ethernet (registered trademark), which enables accurate synchronization means (for example, A non-patent document 2), a highly accurate and highly functional current differential protection relay device capable of performing transmission of a larger capacity than the current state has been proposed (for example, refer to patent document 2).

JP 2000-152486 A JP 2009-225623 A

1986 VOL41 No11 Toshiba Review 11 “Digital Current Differential Protection Relay for Transmission Lines” 2008 IEEJ National Conference 6-302 “Development of Sampling Synchronization Control Applying Wide Area Ethernet”

  The high-accuracy and high-performance protection relay device that enables large-capacity transmission as described above does not perform cyclic transmission as in the past, but packet transmission represented by Ethernet (registered trademark).

  Therefore, the embodiment of the present invention is configured to enable effective and optimization of data to be transmitted from the own device to the other device during packet transmission.

  The digital protection relay device according to the embodiment of the present invention protects the power system by transmitting and receiving the amount of electricity acquired from the power system between the self-end device and the counterpart device via a predetermined transmission path. The analog processing unit of the self-end device samples the amount of electricity acquired from the power system at a predetermined sampling period and converts it into predetermined digital data at each sampling period. The data transmission unit converts the digital data for each predetermined sampling period obtained by the analog processing unit into a predetermined transmission format. The transmission timing control unit extracts predetermined digital data for one sampling of the predetermined transmission format converted by the data transmission unit from the data transmission unit N times within a predetermined time. The transmission transmitting unit transmits predetermined digital data for one sampling of N predetermined transmission formats extracted by the transmission timing control unit to the counterpart device. The transmission receiving unit receives data transmitted from the counterpart device. The arithmetic processing unit performs a relay operation by combining data from the counterpart device received by the transmission receiving unit and data obtained by the analog processing unit.

The block diagram of the digital protection relay apparatus which concerns on Embodiment 1 of this invention. Explanatory drawing of an example of the predetermined | prescribed transmission format obtained by the data transmission part in Embodiment 1 of this invention. Explanatory drawing of operation | movement of the transmission timing control part in Embodiment 1 of this invention. The block diagram of the digital protection relay apparatus which concerns on Embodiment 2 of this invention. Explanatory drawing of the function converted into the new sampling data in the data processing part of Embodiment 2 of this invention. Explanatory drawing of an example of the transmission format in Embodiment 2 of this invention. Explanatory drawing of the other example of the transmission format in Embodiment 2 of this invention. The wave form diagram of the electric quantity by transmission in Embodiment 2 of this invention. The block diagram of the digital protection relay apparatus which concerns on Embodiment 3 of this invention. Explanatory drawing of an example of the transmission format of the process data obtained in the data processing part of Embodiment 3 of this invention. Explanatory drawing of an example of the phasor amount process in the data processing part in Embodiment 3 of this invention. Explanatory drawing of the data discard function of the transmission receiving part in embodiment of this invention. The block diagram which shows the flow of the signal around a transmission receiving part when the transmission receiving part in embodiment of this invention has a data discard function and a normal reception notification function. Explanatory drawing of the data discard function and normal reception notification function of the transmission receiving part in embodiment of this invention. Explanatory drawing of an example of the transmission format of the conventional current differential protection relay device.

(Embodiment 1)
FIG. 1 is a configuration diagram of a digital protection relay device 11 according to Embodiment 1 of the present invention. The digital protection relay device 11 inputs a system electric quantity of current / voltage of the power system 12 and transmits / receives between the own end device and the other end device via a predetermined transmission path 13, and within the own protection section. When it is determined that an accident has occurred, an open command is output to the circuit breaker 14 to disconnect the accident section from the power system 12.

  The current of the power system 12 is detected by the current detector CT, and the voltage is detected by the voltage detector VT and input to the analog processing unit 15 of the digital protection relay device 11. The analog processing unit 15 samples the current detected by the current detector CT of the power system 12 and the voltage detected by the voltage detector VT at a predetermined sampling period, and converts it into predetermined digital data a every sampling period. To do. For example, sampling is performed at a sampling interval Ts, and data at each sampling time point m, m + 1... Is converted into k-bit digital data a. The digital data a obtained by the analog processing unit 15 is input to the data transmission unit 16 and the arithmetic processing unit 20.

  The data transmission unit 16 converts the digital data for each predetermined sampling period fs (sampling interval Ts) obtained by the analog processing unit 15 into a predetermined transmission format. FIG. 2 is an explanatory diagram of an example of a predetermined transmission format obtained by the data transmission unit 16. FIG. 2 shows a transmission format at the sampling time point m, and shows a case where the sampling interval Ts is 3.75 ° in electrical angle.

  The transmission timing control unit 17 extracts predetermined digital data for one sampling of a predetermined transmission format converted by the data transmission unit 16 from the data transmission unit N times within a predetermined time. The signal b is output to the data transmission unit 16. The data transmission unit 16 takes out the transmission format at the sampling time m of the transmission format shown in FIG. 2 N times according to the N-time transmission timing signal b from the transmission timing control unit 17, and transmits and transmits n identical transmission formats c. To the unit 18. The transmission transmitting unit 18 transmits predetermined digital data for one sampling of the n transmission formats extracted by the transmission timing control unit 17 to the counterpart device via the transmission line 13.

  On the other hand, the transmission receiving unit 19 receives data transmitted from the counterpart device and inputs it to the arithmetic processing unit 20. The arithmetic processing unit 20 performs a relay operation by combining the data d received by the transmission receiving unit 19 from the counterpart device and the data a obtained by the analog processing unit 15. Output open command.

  Next, the operation of the digital protection relay device 11 will be described. The analog processing unit 15 of the digital protection relay device 11 acquires the amount of electricity of the power system 12 from the voltage detector VT and the current detector CT and samples it at a predetermined sampling frequency fs (sampling interval Ts). For example, if the predetermined sampling frequency fs is M times the basic frequency f0 in the 50 Hz system, fs = f0 × M.

  This sampled data is converted into predetermined k-bit digital data per sampling. For example, the data is converted into conventional data of 12 bits, 16 bits, 32 bits or more.

  The digital data converted into predetermined k bits is divided into data used for the operation of the local device and data transmitted to the counterpart device, and the data to be transmitted is predetermined by the data transmission unit 16 as shown in FIG. Is converted to the transmission format. Then, when transmitting to the counterpart device, as shown in FIG. 3, 1-sampled data (data of timing m to m + n) sampled at intervals of Ts is transmitted N times in a certain time by the transmission timing control unit 17. Control so that transmission is possible. For example, the m-th sampling data is transmitted N times during the sampling interval from m to m + 1.

  Thereby, the arithmetic processing unit 20 can receive data transmitted from the counterpart device repeatedly N times. Therefore, even if data is temporarily lost due to an error in the transmission path 13, the data can be received at the next timing, and the calculation can be performed without stopping the relay calculation.

  According to the first embodiment, by transmitting the same data N times, even if data is lost due to a temporary transmission failure, a relay operation can be performed with data received at different timing. The protective relay calculation function can be maintained without loss.

(Embodiment 2)
FIG. 4 is a configuration diagram of the digital protection relay device 11 according to the second embodiment of the present invention. The second embodiment is different from the first embodiment shown in FIG. 1 in that the new digital data e for each new sampling data cycle is changed from the predetermined digital data a for each predetermined sampling cycle converted by the analog processing unit 15. The data processing unit 21 for converting to is added.

  Then, the data transmission section 16 transmits the same digital data a having a predetermined sampling period obtained by the analog processing section 15 and new digital data having a new sampling data period converted by the data processing section 21. Convert to format. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  In FIG. 4, the data processing unit 21 has a function of converting the data a at the sampling time m converted by the analog processing unit 15 into new sampling data e. When the data is converted into a predetermined transmission format, the data a at the sampling time m converted by the analog processing unit 15 and the new sampling data e are converted into the same transmission format and transmitted from the transmission transmitting unit 18.

  FIG. 5 is an explanatory diagram of a function of converting into new sampling data e in the data processing unit 21. Now, assuming that the electrical quantity of the power system 12 obtained by the analog processing unit 15 is the sampling frequency fs multiplied by M with respect to the basic frequency f0 in the 50 Hz system, fs = f0 × M, and M Is 96 times, the sampling frequency fs is 4800 Hz, and the sampling interval Ts is 3.75 °.

  The data processing unit 21 processes the data processed by the analog processing unit 15 into predetermined sampling data e. For example, as shown in FIG. 4, when converting 3.75 ° data to 7.5 °, 15 °, and 30 ° data, two 3.75 ° data are added and averaged to 7.5 °. Get. Then, two 7.5 ° data are added and averaged to obtain 15 °. In addition, 15 ° data can be obtained by averaging four pieces of 3.75 ° data, or 30 ° data can be processed by the same method. Further, as a method for obtaining new sampling data e, there is a data thinning process in addition to the averaging. Known techniques can be used for these data processing techniques.

  FIG. 6 is an explanatory diagram of an example of a transmission format in the second embodiment. It is explanatory drawing of an example of the transmission format in the case of transmitting simultaneously the sampling data a obtained by the analog processing part 15, and the new sampling data e obtained by the data processing part 15.

  As shown in FIG. 6, the sampling data a (3.75 ° sampling data) obtained by the analog processing unit 15 and the new sampling data e (7.5 °, 15 ° obtained by the data processing unit 15). , 30 ° data) in the same transmission format. That is, in the conventional relay calculation, for example, only sampling data at intervals of 30 ° are transmitted, but in the second embodiment of the present invention, not only 30 ° data but also finer sampling is performed with the same transmission format. Data of 75 °, 7.5 °, and 15 ° are also transmitted.

  As shown in FIG. 7, sampling data a (3.75 ° sampling data) obtained by the analog processing unit 15 and new sampling data e (7.5 °, sampling data obtained by the data processing unit 15). 15 ° and 30 ° data) may be converted into different transmission formats and transmitted separately.

  In this way, by dividing the transmission format, the relay operation timing is different, for example, a current differential relay that must operate at high speed, and high speed performance such as overload. Data necessary for what is not required can be transmitted separately. Thereby, not only the relay calculation burden on the receiving side can be reduced, but also the transmission load can be reduced.

  FIG. 8 is a waveform diagram of the amount of electricity due to transmission in the second embodiment, FIG. 8A is a waveform diagram of the amount of electricity based on 3.75 ° data, and FIG. 8B is an amount of electricity based on 30 ° data. FIG. FIG. 8 shows a waveform including a triple harmonic. As shown in FIG. 8, the smaller the sampling angle, the more accurately the waveform reproduction on the side of the counterpart device that has received the data with the harmonics superimposed, and the highly accurate waveform reproduction becomes possible.

  In addition, the processing of the sampling processing required by the counterpart device that received the data has conventionally increased the processing load of the relay, but by transmitting the preprocessed data, It eliminates the burden of computation processing and enables high-speed relay computation.

  According to the second embodiment, in addition to the effects of the first embodiment, more detailed sampling data is transmitted in addition to the sampling data at intervals necessary for the relay calculation, so that highly accurate waveform reproduction is possible. Therefore, it is possible to realize a countermeasure against an inrush current that has been realized by a transformer protection device that has not been realized so far, and a countermeasure against malfunction caused by CT saturation at the time of an external accident that has been realized by a busbar protection device. Further, since it is not necessary to process the detailed data necessary for the relay calculation at the counterpart device that has received the data, the calculation processing load is reduced, and high-quality and high-speed calculation can be performed.

(Embodiment 3)
FIG. 9 is a configuration diagram of the digital protection relay device 11 according to the third embodiment of the present invention. The third embodiment is different from the first embodiment shown in FIG. 1 in that data to be converted from predetermined digital data a obtained by the analog processing unit 15 for each predetermined sampling period into digital data g required for relay calculation. A processing unit 22 is additionally provided. Then, the data transmission unit 16 converts the predetermined digital data a having a predetermined sampling period obtained by the analog processing unit 15 and the digital data g obtained by the data processing unit 22 into the same transmission format. Convert. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  In FIG. 9, the data processing unit 22 has a function of converting the data a at the sampling time m converted by the analog processing unit 15 into data g necessary for the relay calculation. When the data transmission unit 16 converts the data into a predetermined transmission format, the data a at the sampling time m converted by the analog processing unit 15 and the data g necessary for the relay calculation processed from the data a at the sampling time m. Are converted to the same transmission format.

  The data processing unit 22 performs sample electric quantity processing and phasor amount processing. In the sample electric quantity processing, target electric quantity (normal phase / reverse phase / zero phase) in the target coordinate method and α / β / zero data of the αβ0 circuit in the Clark coordinate method are calculated. On the other hand, in the phasor amount processing, the real part (Re) and the imaginary part (Im) of the complex number representation (phasor) of the electric quantity of the data sampled by the analog processing unit 15 are calculated.

  FIG. 10 is an explanatory diagram of an example of a transmission format of the processed data g obtained by the data processing unit 22 of the third embodiment. FIG. 10 shows a transmission format at the sampling time m. Data obtained when the sampling interval Ts obtained in the analog processing unit 15 is 3.75 ° in electrical angle, sample amount obtained in the sample electric quantity processing of the data processing unit 22, and obtained in the phasor amount processing of the data processing unit 22. The real part and the imaginary part are transmitted in the same transmission format. Note that these data may be converted into different transmission formats and transmitted separately as shown in FIG. 7 of the second embodiment. Also in this case, the sample amount and the phasor amount processed by the data processing unit 22 can be transmitted separately into those that do not require high speed and those that do not.

  Next, as an example of the data g necessary for the relay calculation obtained by the data processing unit 22, in the sample electric quantity processing, for example, the positive phase / reverse phase / zero phase as the symmetrical electric quantity, α · β of the αβ0 circuit • Some data has been mode converted to zero. As an example of the sample electric quantity processing, an example of positive phase electric quantity is shown.

3I1 = Ia + αIb + α2Ic
3V1 = Va + αVb + α2Vc
I1: Positive phase current V1: Positive phase voltage On the other hand, phasor amount processing has been established as a known technique. An example is shown in FIG. As shown in FIG. 11, the electrical quantity of the data a sampled by the analog processing unit 15 is separated into two orthogonal quantities and processed. A real number part (Re) and an imaginary number part (Im) of a complex number expression (phasor) are obtained as two orthogonal quantities in the DFT operation on the fundamental wave.

  According to the third embodiment, in addition to the effects of the first embodiment, since the data g required for the relay calculation is obtained and transmitted by the data processing unit 22, the data necessary for the relay calculation at the counterpart device that has received the data g. There is no need to process into g. Therefore, the calculation processing burden of relay relay can be reduced, and high-quality and high-speed calculation can be performed.

  Next, when the transmission receiving unit 19 correctly receives predetermined digital data for one sampling of a predetermined transmission format transmitted from the counterpart device, the transmission receiving unit 19 receives the predetermined one sampling for the same one sample that has arrived thereafter. The digital data may be discarded.

  FIG. 12 is an explanatory diagram of the data discard function of the transmission receiver 19. As shown in FIG. 12, when receiving data from the counterpart device, the transmission receiving unit 19 confirms the frame number added to the transmission frame and confirms whether or not correct data has been received. When it is determined that correct data has been received, a return reception signal is output to the data transmission unit 16 and the same data confirmed by the frame number that has arrived thereafter is discarded. As a result, it is possible to perform a relay calculation using only the data correctly received even once by the arithmetic processing unit 20, and the load of the arithmetic processing can be reduced.

  Further, in addition to the data discarding function, when correctly receiving predetermined digital data for one sampling of a predetermined transmission format transmitted from the counterpart device, the transmission receiving unit 19 You may make it provide the normal reception notification function which notifies that it received correctly. If the data transmission unit 16 receives a notification from the transmission reception unit 19 that the data has been correctly received, the data transmission unit 16 notifies the counterpart device that the data has been correctly received.

  In addition, when the transmission receiving unit 19 receives a notification from the counterpart apparatus that it has been received correctly, the transmission timing control unit 17 stops the transmission of future transmission data until the next data transmission timing. Also good.

  FIG. 13 is a configuration diagram showing the flow of signals around the transmission receiver 19 when the transmission receiver 19 has a data discard function and a normal reception notification function. The transmission receiving unit 19 discards the data input after that at the timing when the predetermined digital data for one sampling of the predetermined transmission format transmitted from the counterpart device can be correctly received, and the data transmission unit 16 The normal reception signal j to that effect is output. When the data transmission unit 16 receives the normal reception signal j, the data transmission unit 16 creates a transmission format c1 indicating that the data is correctly received by the counterpart device and transmits it from the transmission transmission unit 18.

  On the other hand, when the other device receives a signal notifying that data has been correctly received, the transmission receiving unit 19 outputs a notification signal h to the transmission timing control unit 17. When receiving the notification signal h, the transmission timing control unit 17 outputs a control command b1 that prevents the data transmission unit 16 from transmitting data until the next data transmission timing.

  FIG. 14 is an explanatory diagram of a data discard function and a normal reception notification function of the transmission receiving unit 19. As shown in FIG. 14, when receiving data from the counterpart device, the transmission receiving unit 19 confirms the frame number added to the transmission frame and confirms whether or not correct data has been received. When it is determined that correct data has been received, a return reception signal is output to the data transmission unit 16 and the same data confirmed by the frame number that has arrived thereafter is discarded.

  In addition to this data discard function, the transmission receiving unit 19 outputs a normal reception signal j to the data transmission unit 16 that the data has been correctly received. As a result, the data transmission unit 16 transmits information indicating that the data has been correctly received to the counterpart device using, for example, a part of a data frame in a predetermined transmission format. Alternatively, the data is transmitted in a transmission format different from the data transmission format and transmitted to the counterpart device.

  When the transmission receiving unit 19 of the counterpart device receives a signal notifying that data has been correctly received, it outputs a notification signal h to the transmission timing control unit 17. When receiving the notification signal h, the transmission timing control unit 17 outputs a control command b1 that prevents the data transmission unit 16 from transmitting data until the next data transmission timing. That is, the terminal device that has been notified that the signal has been correctly received is temporarily stopped until the next data transmission timing.

  As a result, it is possible to perform a relay operation only with data correctly received even once by the arithmetic processing unit 20, and not only reduce the load of the arithmetic processing but also the transmission load.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 ... Digital protective relay apparatus, 12 ... Power system, 13 ... Transmission path, 14 ... Circuit breaker, 15 ... Analog processing part, 16 ... Data transmission part, 17 ... Transmission timing control part, 18 ... Transmission transmission part, 19 ... Transmission receiving unit, 20... Arithmetic processing unit, 21... Data processing unit, 22.

Claims (7)

In the digital protection relay device that protects the power system by transmitting and receiving the amount of electricity acquired from the power system between the self-end device and the counterpart device via a predetermined transmission line,
The self-end device samples the amount of electricity acquired from the power system at a predetermined sampling period and converts it into predetermined digital data for each sampling period; and
A data transmission unit for converting the digital data for each predetermined sampling period obtained by the analog processing unit into a predetermined transmission format;
A transmission timing control unit for extracting predetermined digital data for one sampling of a predetermined transmission format converted by the data transmission unit N times from the data transmission unit within a predetermined time;
A transmission transmitter for transmitting predetermined digital data for one sampling of N predetermined transmission formats extracted by the transmission timing control unit to a counterpart device;
A transmission receiving unit for receiving data transmitted from the counterpart device;
A digital protection relay device comprising: an arithmetic processing unit that performs a relay operation by combining data from a counterpart device received by the transmission receiving unit and data obtained by the analog processing unit.   A data processing unit is provided for converting predetermined digital data for each predetermined sampling period converted by the analog processing unit to new digital data for each new sampling data period, and the data transmission unit is configured to convert the analog processing unit 2. The predetermined digital data having a predetermined sampling period obtained in step 1 and the new digital data having a new sampling data period converted by the data processing unit are converted into the same transmission format. Digital protective relay device.   The data transmission unit converts digital data for each predetermined sampling obtained by the analog processing unit and new digital data of a new sampling data period converted by the data processing unit into the same transmission format. 3. The digital protection relay device according to claim 2, wherein the digital protection relay device converts to a separate transmission format.   A data processing unit is provided for converting from predetermined digital data obtained at the predetermined sampling period obtained by the analog processing unit into digital data necessary for relay calculation, and the data transmission unit is obtained by the analog processing unit. 3. The digital protection relay according to claim 1 or 2, wherein predetermined digital data having a predetermined sampling period and digital data necessary for relay calculation obtained by the data processing unit are converted into the same transmission format. apparatus.   The data transmission unit replaces the digital data for each predetermined sampling obtained by the analog processing unit and the digital data necessary for the relay operation obtained by the data processing unit into the same transmission format. 5. The digital protection relay device according to claim 4, wherein the digital protection relay device converts the transmission formats into different transmission formats.   When the transmission receiving unit correctly receives predetermined digital data for one sampling of a predetermined transmission format transmitted from the counterpart device, the predetermined digital data for the same one sampling that has arrived thereafter The digital protection relay device according to claim 1, wherein the digital protection relay device is discarded.   When the transmission receiving unit correctly receives predetermined digital data for one sampling of a predetermined transmission format transmitted from the counterpart device, the predetermined digital data for the same one sampling that has arrived thereafter In addition, the data transmission unit is notified that the data has been correctly received, and when the data transmission unit receives a notification from the transmission reception unit that the data has been correctly received, If the transmission receiving unit receives a notification from the counterpart device that it has been received correctly, the transmission timing control unit sends future transmission data to the next 7. The digital protection relay device according to claim 6, wherein the digital protection relay device is stopped until data transmission timing.

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