WO2022243401A1 - Transmission apparatus and method for protection signaling of power system - Google Patents

Transmission apparatus and method for protection signaling of power system Download PDF

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Publication number
WO2022243401A1
WO2022243401A1 PCT/EP2022/063504 EP2022063504W WO2022243401A1 WO 2022243401 A1 WO2022243401 A1 WO 2022243401A1 EP 2022063504 W EP2022063504 W EP 2022063504W WO 2022243401 A1 WO2022243401 A1 WO 2022243401A1
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WO
WIPO (PCT)
Prior art keywords
transmission
protection
protection signaling
signaling
transmission unit
Prior art date
Application number
PCT/EP2022/063504
Other languages
French (fr)
Inventor
Zhong Hua SHU
Mei Juan JIN
Qing Bing ZHANG
Zhi Tao PAN
Original Assignee
Siemens Aktiengesellschaft
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Filing date
Publication date
Application filed by Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO2022243401A1 publication Critical patent/WO2022243401A1/en

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Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08C—TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
    • G08C23/00—Non-electrical signal transmission systems, e.g. optical systems
    • G08C23/06—Non-electrical signal transmission systems, e.g. optical systems through light guides, e.g. optical fibres
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00016—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using a wired telecommunication network or a data transmission bus
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0061—Details of emergency protective circuit arrangements concerning transmission of signals
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00016—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using a wired telecommunication network or a data transmission bus
    • H02J13/00017—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using a wired telecommunication network or a data transmission bus using optical fiber
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00019—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using optical means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • H02J13/00028—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment involving the use of Internet protocols
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
    • H02J13/00036—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers
    • H02J13/0004—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers involved in a protection system
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation

Definitions

  • the present invention relates to the field of power systems, and in particular, to a transmission apparatus and method for protection signaling of a power system.
  • a protective relay is an important device in a power system and is designed to detect the presence of a fault or an exception in the power system, and to transmit protection signaling to directly isolate and cut out the faulty part.
  • a transmission apparatus for protection signaling is responsible for transmitting the protection signaling from the protec tive relay to a remote power station in a secure and timely manner, so as to im plement WAN protection of a high-voltage transmission line.
  • each power station includes a transmission apparatus for protection signaling, and the transmission apparatus for protection signaling is configured for protection sig naling transmission with a same power station. It is shown in FIG. 1 that each power station includes two transmission apparatuses for protection signaling, namely a transmission apparatus 101 for protection signaling, a transmission apparatus 102 for protection signaling, a transmission apparatus 103 for protec tion signahng, a transmission apparatus 104 for protection signaling, a trans mission apparatus 105 for protection signaling, and a transmission apparatus 106 for protection signaling.
  • each transmission apparatus for protection signaling can perform protection sig- naling transmission only with a same transmission apparatus for protection sig naling of one power station, that is, point-to-point transmission.
  • the transmission apparatus 101 for protection signaling in FIG. 1 can communi cate only with the transmission apparatus 103 for protection signaling. If the power station needs to perform protection signaling transmission with a second power station, one more transmission apparatus for protection signaling needs to be added to the power station.
  • the transmission apparatus 102 for protection signaling is added to the power station 10, to communicate with the transmission apparatus 105 for protection signaling in the power station 12, and the transmission apparatus 104 for protection signaling is added to the power station 11, to communicate with the transmission apparatus 106 for protection signaling in the power station 12.
  • the present invention provides a transmission apparatus for pro tection signaling of a power system, the power system including a plurality of power stations that are connected to each other over a WAN, where each power station has one transmission apparatus, and the transmission apparatus in cludes: a first transmission unit configured to perform protection signaling trans mission with a first power station; a second transmission unit configured to perform protection signaling transmission with a second power station; and a processor configured to receive protection signaling transmitted by the first transmission unit and determine whether to deliver the protection signaling or forward the protection signaling to the second transmission unit based on the protection signaling, and configured to receive protection signaling transmitted by the second transmission unit and determine whether to dehver the protection signaling or forward the protection signahng to the first transmission unit based on the protection signaling.
  • the transmission apparatus for protection signahng may perform data transmis sion with two power stations respectively through two transmission units, which still implements point-to-point transmission for a same transmission unit, and still guarantees independence and security of protection signaling transmission.
  • a fault that occurs in one transmission unit will not affect normal operation of the other transmission unit, which guarantees timeliness and relia bility of protection signahng transmission to the greatest extent on the basis of implementing point -to -multipoint transmission.
  • the transmission apparatus further includes : a set of interface cards through which the processor transmits the protection signaling to a relay protection apparatus of a power station where the processor is located.
  • the first transmission unit performs direct protection signaling transmission with the first power station over the WAN; and the second transmission unit performs direct protection signahng transmission with the second power station over the WAN.
  • each of the first transmission unit and the second transmission unit includes : a LID module for protection signaling transmission over one TDM port; or if the connection port of the WAN is a fiber-optic port, each of the first transmission unit and the second transmission unit includes : a LID module and a FOM module, where the FOM module is config- ured to perform optical signal modulation or optical signal encapsulation on the protection signaling, and the LID module is configured to pre-process the protec tion signaling.
  • the first transmission unit performs protection signaling transmission with the first power station via a multiplexer
  • the second transmission unit performs protection signaling transmission with the second power station via the multiplexer
  • the first transmission unit communicates directly with the first power station via the FOM module
  • the second transmission unit communicates directly with the second power station via the FOM module
  • the transmission apparatus further includes ⁇ an alarm unit configured to transmit one piece of monitoring information when the transmission apparatus does not perform protection signaling trans mission, to monitor a communication status of the WAN and output an alarm signal.
  • a struc ture of a packet transmitted over the TDM port sequentially includes synchroni zation information, type information, address information, data information, and check information.
  • a transport protocol for the TDM port of the LID module of the first transmission unit is different from that for the TDM port of the LID module of the second transmission unit.
  • the first transmission unit and the second transmission unit perform protection signaling transmission with a multiplexer over an E 1 channel, the multiplexer is configured to perform protection signahng transmission with the first power station and the second power station, the first transmission unit has an El port, and the second transmission unit has an El port.
  • each of the first transmission unit and the second transmission unit includes a LID module
  • one of the first transmission unit and the second transmission unit serves as a primary transmission unit
  • the other serves as a backup transmission unit
  • the backup transmission unit is capable of repheating the protection signaling transmitted by the primary transmission unit.
  • the El channel includes a frame header and N sets of slots, and each set of slots corre sponds to one set of protection signaling, where N is a positive integer greater than or equal to 4.
  • the pro tection signaling received by the transmission apparatus is a plurahty of pieces of consecutive protection signaling
  • information about each piece of protection sig nahng is the same
  • the first transmission unit or the second transmission unit determines whether the number of pieces of consecutively received protection signaling that are the same is greater than or equal to a preset threshold, and if a determining result is yes, transmits the protection signaling to the processor.
  • the present invention further provides a power station for a power system, in cluding the transmission apparatus for protection signahng of a power system according to any one of the foregoing embodiments.
  • the present invention further provides a power system, including a plurahty of power stations that are connected to each other over a WAN, where each power station has one transmission apparatus, and the transmission apparatus is the transmission apparatus according to any one of the foregoing embodiments.
  • the present invention further provides a transmission method for protection signaling of a power system, the power system including a plurality of power sta tions that are connected to each other over a WAN, where each power station has one transmission apparatus for protection signaling, and the transmission method includes : receiving protection signaling from a first power station; determining, based on information about the protection signaling, that a destination of the protection signaling is a second power station; and forwarding the protection signaling to the second power station.
  • the trans mission method further includes : transmitting one piece of monitoring information over a corresponding WAN when the transmission apparatus does not perform protection signaling transmission, to monitor a communication status of the WAN.
  • a packet structure of the protection signahng sequentially includes synchronization in formation, type information, address information, data information, and check information.
  • a transport protocol or transmission interface for the received protection signaling is different from that used for forwarding the protection signaling.
  • the transmission method further includes : determining whether the number of pieces of consecutively received protection signaling that are the same reaches a preset threshold; and if a determining result is yes, determining, based on the information about the protection signaling, that the destination of the protection signaling is the second power station.
  • receiving protection signaling from a first power station includes ⁇ receiving, over an E 1 channel, the protection signaling of the first power station that is transmitted by a multiplexer, where the El channel includes a frame header and N sets of slots, and each set of slots corre sponds to one set of protection signaling, where N is a positive integer greater than or equal to 4.
  • the transmission method further includes : replicating the protection signaling in real time; and transmit ting the protection signaling and the replicated protection signaling over two ports, respectively.
  • FIG. 1 is a schematic structural diagram of a power system including a transmis sion apparatus for protection signaling in the prior art
  • FIG. 2A is a schematic structural diagram of a transmission apparatus for pro tection signaling of a power system according to an embodiment of the present invention
  • FIG. 2B and FIG. 2C are schematic structural diagrams of direct transmission of protection signaling between a transmission apparatus for protection signaling of a power system and another power station according to the present invention
  • FIG. 2D is a schematic structural diagram of transmission of protection signaling between a transmission apparatus for protection signaling of a power system and another power station via a multiplexer according to the present invention
  • FIG. 2E is a schematic structural diagram of transmission of four sets of protec tion signaling at a time by a transmission apparatus for protection signaling of a power system according to the present invention
  • FIG. 2F is a schematic structural diagram of backup of protection signaling by a transmission apparatus for protection signaling of a power system according to the present invention.
  • FIG. 3 is a schematic flowchart of a transmission method for protection signaling of a power system according to an embodiment of the present invention.
  • a power system includes a plurality of power stations that are connected to each other over a WAN to perform protection signaling transmission.
  • each power station has one transmission apparatus for protection sig ⁇ naling, and the transmission apparatus can perform protection signaling trans ⁇ mission in different directions.
  • a specific structure of the transmission apparatus is as shown in FIG. 2 A.
  • the power station 11 has one transmission apparatus 111
  • the power station 12 has one transmission apparatus 121
  • the power station 10 has one transmission apparatus 20.
  • the power station 11 and the power station 10 can perform protection signaling transmission with each other, and the power station 12 and the power station 10 can also perform protection signaling transmission with each other.
  • FIG. 1 the power station 11 and the power station 10 can perform protection signaling transmission with each other, and the power station 12 and the power station 10 can also perform protection signaling transmission with each other.
  • the power station 10 may implement protection sig ⁇ naling transmission in the two directions D1 and D2.
  • protection signaling to be transmitted between the power station 11 and the power station 12 may be forwarded by the power station 10, as shown by the ar ⁇ rows in FIG. 2C.
  • the power station 11 may perform protection signaling trans ⁇ mission with the power station 10 in the direction D3, and may also perform pro ⁇ tection signaling transmission with the power station 12 in the direction D4.
  • the transmission apparatus in the present invention can implement point -to -multipoint transmission of protection signaling between the power sta ⁇ tions.
  • the present invention provides a transmission apparatus for protection signaling of a power system.
  • the transmission apparatus can implement point -to -multipoint signaling transmission, that is, the transmission apparatus may perform protection signaling transmission in different transmission direc- tions.
  • FIG. 2A is a schematic structural diagram of the transmission apparatus for pro tection signaling of a power system according to the present invention.
  • the transmission apparatus 20 for protection signahng of a power system includes a first transmission unit 201, a second transmission unit 202, and a processor 203.
  • the first transmission unit 201 is configured to perform protection signaling transmission with a first power station 11.
  • the second transmission unit 202 is configured to perform protection signaling transmission with a second power sta tion 12.
  • the processor 203 is configured to receive protection signaling transmit ted by the first transmission unit 201 and determine whether to deliver the pro tection signahng or forward the protection signahng to the second transmission unit 202 based on the protection signaling, and configured to receive protection signaling transmitted by the second transmission unit 202 and determine whether to dehver the protection signaling or forward the protection signaling to the first transmission unit 201 based on the protection signaling.
  • a power station where the transmission apparatus is located is a power station 10.
  • a WAN is con nected between the first transmission unit 201 and the first power station 11, and the first transmission unit 201 can perform direct protection signaling transmis sion with the first power station 11 over the WAN, that is, physical connection between the first transmission unit 201 and the first power station 11 can guar antee protection signahng transmission therebetween.
  • a WAN is con nected between the second transmission unit 202 and the second power station 12, and the second transmission unit 202 can perform direct protection signahng transmission with the second power station 12 over the WAN.
  • the transmission apparatus 20 is connected to the transmission apparatus 111 in the first power station 11 and the transmission apparatus 121 in the second power station 12.
  • both the first transmission unit 201 and the second transmission unit 202 may be connected to a multiplexer 21 (MUX), and the multiplexer 21 may be physically connected to and perform protection signaling transmission with a plurality of other power stations, that is, the first transmission unit 201 performs protection signahng transmission with the first power station via the multiplexer 21, and the second transmission unit 202 performs protection signahng transmission with the second power station via the multiplexer 21.
  • MUX multiplexer 21
  • the multiplexers 21 are mainly used to combine a plu rality of channels of low-rate data and convert the combined low-rate data into higher-rate data for transmission.
  • the transmission apparatus in this embodi ment can also be matched with the multiplexer 21, to be further well compatible with a hardware structure in the prior art.
  • the processor 203 is configured to receive the protection signaling transmitted by the first transmission unit 201 and determine whether to dehver the protection signaling or forward the protection signaling to the second transmission unit 202 based on the protection signaling, and configured to receive the protection sig naling transmitted by the second transmission unit 202 and determine whether to deliver the protection signaling or forward the protection signaling to the first transmission unit 201 based on the protection signaling.
  • Information about the protection signaling includes an address of a sending end of the protection sig naling, namely a source address. Each source address has a pre-matched desti nation address. Therefore, the processor 203 determines, based on preset infor mation, whether the destination address is matched.
  • the processor 203 determines, based on a DATA field in the protection signaling, whether to dehver or forward the protection signaling, that is, the processor 203 determines whether to send the protection signaling down stream or forward the protection signahng to the second transmission unit 202.
  • the protection signaling can be transmitted to the second power station 12 through the second transmission unit 202, to implement communication between the first power station 11 and the second power station 12, that is, implement a T-shaped communication architecture as shown by dotted lines in FIG. 2B.
  • the protection signaling transmitted by the second power station 12 may also be forwarded to the first power station 11 through the transmission appa ratus for protection signaling.
  • the processor herein may be at least one of the following apparatuses: a microprocessor, a digital signal processor (DSP), and a programmable logic array (FPGA).
  • the transmission apparatus for protection signaling may perform data transmis sion with two power stations respectively through two transmission units, which still implements point-to-point transmission for a same transmission unit, and still guarantees independence and security of protection signaling transmission.
  • each of the first transmission unit 201 and the second transmission unit 202 may include a line interface digital (LID) module 2011, and the LID module 2011 performs protection signaling transmission over a time-division multiplexing (TDM) port.
  • the LID module 2011 can pre-process the protection signaling into a packet structure as hsted in Table 1, to implement different digital transmission coding manners (for example, AMI coding and HDB3 coding), match different TDM ports, calculate a transmission bit error rate, monitor a transmission status of the line in real time, quickly switch to a backup line when a fault occurs, and reliably receive protection sig naling, and so on.
  • the first transmission unit 201 includes a LID module 2011 and a fiber-optic modem (FOM) module 2012
  • the second transmission unit 202 may also include a LID mod ule 2011 and a FOM module 2012.
  • the FOM module 2012 of the first transmission unit 201 after receiving the protection signaling, performs op tical signal modulation on the protection signaling and transmits the modulated protection signaling to the LID module 2011 of the first transmission unit 201 for pre-processing, and the LID module 2011 of the first transmission unit 201 fur ther transmits the pre-processed protection signaling to the processor 203.
  • the processor 203 If the processor 203 identifies, based on the protection signaling, that the protection signaling should be forwarded to the second power station 12, the processor 203 transmits the protection signaling to the LID module 2011 of the second trans mission unit 202, the LID module 2011 of the second transmission unit 202 pre-processes the protection signaling, the FOM module 2012 of the second transmission unit 202 performs optical signal encapsulation on the pre-processed protection signaling, and the FOM module 2012 of the second transmission unit 202 transmits the pre-processed protection signaling to the second power station 12 over an optical port thereof (not shown in the figure).
  • the port of the FOM module 2012 may be directly connected to the second power station through an optical fiber.
  • protocols used by the TDM ports of the two transmission units may be the same or different.
  • structures of the two transmission units are the same.
  • the used protocols are different, for example, one TDM port uses a 64 Kbps X.21 port or G.703.1 port, and the other TDM port uses a 2 Mbps G.703.6 port or fiber-optic port.
  • different protocols adapt to transmission hnes with different requirements.
  • the transmission unit corresponding to the op tical fiber line may have both the LID module 2011 and the FOM module 2012, and the transmission unit corresponding to the digital line may have one LID module 2011, which may be specifically selected according to actual requirements, that is, relevant hardware configuration and software configuration may be im ⁇ plemented based on actual physical connection.
  • a structure of a packet transmitted over the TDM port sequentially includes synchronization information (SYNC), type information (TYPE), address infor ⁇ mation (ADR), data information (DATA), and check information (CRC).
  • SYNC denotes a packet synchronization signal
  • TYPE denotes a type of the packet
  • the address information includes a source address of the packet
  • the check information is used for a consistency check.
  • the transmission unit After receiving the protection signahng, the transmission unit first performs a consistency check. During the consistency check, whether a check value included in the check in ⁇ formation is correct is first detected.
  • the check value is correct, whether the address information matches a preset address of a power station that can com ⁇ municate with the transmission unit is determined. If the address information matches the preset address, the consistency check succeeds, then the protection signaling is decoded, and the decoded protection signaling is sent downstream or forwarded. How to decode the protection signaling belongs to the prior art, and is not repeated herein. If the consistency check fails, the protection signaling is discarded.
  • a delivery and forwarding process is de ⁇ scribed as follows: (a) after receiving protection signaling, the transmission ap ⁇ paratus 20 determines a start location of a packet of the protection signaling based on SYNC, and if the determining fails, the packet is discarded, or if the determining succeeds, step (b) is performed; (b) whether a type of the packet is correct is determined based on TYPE, and if the type is incorrect, the packet is discarded, or if the type is correct, step (c) is performed; (c) whether the CRC check succeeds is determined, and if the check fails, the packet is discarded, or if the check succeeds, step (d) is performed; (d) whether the ADR matches a pre-configured destination address is determined, and if the ADR does not match the pre-configured destination address, the packet is discarded, or if the ADR matches the pre-configured destination address, step (e) is performed; and (e) DATA
  • a time for transmitting the protection signaling is very critical, and has been specified in the standard IEC60834-1.
  • a transmission speed of the TDM port may be selected as 2 Mbps.
  • a delay caused by forwarding may be very small, for example, less than 0.1 ms.
  • the transmission apparatus 20 further includes a set of in terface cards 204, and the processor 203 sends the protection signaling down stream through the interface cards 204.
  • Sending the protection signaling down stream herein refers to transmitting the protection signaling to a relay protection apparatus of a same power station.
  • FIG. 2 shows four interface cards 204, and the number of interface cards 204 may be adjusted according to actual requirements. Four sets of protection signahng may be transmitted through each interface card 204 at a time.
  • the transmission apparatus 20 further includes an alarm unit 205 configured to monitor an operation status of the transmission apparatus. Since the transmission apparatus itself is a transceiver apparatus, whether the trans mission apparatus performs protection signaling transmission may be learned, and when the transmission apparatus does not perform protection signaling transmission, the transmission apparatus will continuously transmit monitoring information, to monitor a status of a communication line of the WAN.
  • the alarm unit 205 may also give an alarm through self- detection, for example, may give an alarm when transmission fails or power is insufficient.
  • the transmission apparatus 20 further includes a power module 206, and the power module 206 is configured to provide power.
  • both the first transmission unit 201 and the sec ond transmission unit 202 may be connected to the multiplexer 21 over an El channel and perform protection signaling transmission via the multiplexer 21, and the multiplexer 21 is configured to perform protection signahng transmission with the first power station 11 and the second power station 12.
  • Each transmis sion unit has one El port, and over the two El ports, protection signahng trans mission in two directions is implemented.
  • each El port may support transmission of two signaling sets at a time, and each signaling set may include four or eight pieces of signahng.
  • Such a technology is referred to as a channelized El (CEl) technology.
  • the transmission apparatus including two transmission units have four El ports, and via the multiplexer 21, may im plement protection signaling transmission in four directions.
  • the CEl technology with which the transmission apparatus can perform protec tion signahng transmission in four directions A, B, C, and D at a time uses pulse code modulation (PCM) for decoding or encoding.
  • PCM pulse code modulation
  • a transmission speed thereof is 2.048 Mbps
  • 8 bits form one slot (Ts)
  • 32 slots form one frame (F).
  • the 32 slots may be divided into one frame header and a plurality of sets of slots, for example, N sets of slots, and each set of slots corresponds to one set of protection signaling, where N is a positive integer greater than or equal to 4.
  • N 4
  • slots 1 to 5 are allocated to the first set of protection signaling
  • slots 6 to 10 are allocated to the second set of protection signaling
  • slots 11 to 31 are reserved for a subsequent extended function, for example, five slots fall into one set.
  • slots 1 to 5 are allocated to the third set of protection signaling
  • slots 6 to 10 are allocated to the fourth set of protection signaling
  • slots 11 to 31 are reserved for a subsequent extended function.
  • Table 2 and Table 3 respectively list a frame structure of the El channel corresponding to the first transmission unit 201 and a frame structure of the El channel corre sponding to the second transmission unit 202.
  • a frame alignment signal (FAS) denotes a frame header, which is located in the slot 0.
  • a structure of each piece of protection signaling may be as listed in Table 1.
  • the transmission appa- ratus After receiving protection signaling over the El channel, the transmission appa- ratus parses the protection signaling, for example, performs a consistency check after removing a frame header.
  • a manner of the consistency check is the same as that in the foregoing embodiment, and will not be repeated herein.
  • the LID module of one of the two transmission units may serve as a backup transmission unit
  • the LID module of the other transmission unit may serve as a primary transmission unit.
  • the first transmission unit 201 serves as the primary transmission unit, and has one El port.
  • the second transmission unit 202 serves as the backup transmission unit, also has one El port, and can repli cate the protection signahng transmitted by the first transmission unit 201, so that the protection signaling and the rephcated protection signaling that are the same are simultaneously transmitted over the two El ports, respectively.
  • a transmission apparatus on a sending side will replicate received protection signaling, and transmit the protection signaling and the rep licated protection signaling that are the same over two El ports, respectively.
  • a transmission apparatus on a receiving side identifies that a primary trans mission unit thereof is faulty, it automatically switches to a backup transmission unit to receive the protection signahng, to avoid loss of the protection signaling.
  • the transmission apparatus that receives the protection signahng identifies that a port or transmission line in the primary transmission unit of the transmission apparatus that transmits the protection signaling is faulty, it au tomatically switches to the backup transmission unit to receive the protection signaling, which can guarantee normal transmission and reception of the protec tion signaling.
  • two different sets of protection signaling may be transmitted over each El channel, that is, the transmission apparatus can sup port both one-to-many transmission and 1 + 1 hne backup transmission.
  • the transmission apparatus can perform protection signaling trans mission in both directions A and B at a time, and back up protection signaling in both directions A and B, where the dotted line denotes the backup line.
  • the protection signaling received by the transmission apparatus is a plurality of pieces of consecutive protection signaling, information about each piece of protection signaling is the same, and the first transmission unit 201 or the second transmission unit 202 determines whether the number of pieces of consecutively received protection signaling that are the same reaches a preset threshold, and if a determining result is yes, transmits the protection signaling to the processor 203.
  • a plurality of pieces of same protection signaling are usually sent consecutively.
  • the first transmission unit 201 or the second transmission unit 202 determines, based on the number of pieces of received same protection signaling, whether to transmit the protection signahng. When the number of pieces of received same protection signaling reaches a preset threshold, it indicates that the protection signaling may be securely received.
  • the present invention further provides a transmission method for protection signaling of a power system.
  • the power system includes a plurality of power sta tions.
  • the power stations are connected to each other over a WAN.
  • Each power station has one transmission apparatus for protection signahng.
  • the transmission method includes the following steps.
  • step 301 protection signaling from a first power station is received.
  • the protection signaling transmitted by the first power station may be directly received over a physically connected WAN or via a multiplexer.
  • protection signaling is an optical signal
  • the protection signahng in the form of the optical signal is received, the optical signal is processed, and how to process the optical signal belongs to the prior art, and is not repeated herein.
  • a destination of the protection signahng is determined as a second power station based on information about the protection signaling.
  • the protection signaling includes a source address. Whether a pre-configured destination address is matched is determined based on the source address, and whether the protection signaling needs to be sent downstream or forwarded to the second power station is determined based on the protection signaling.
  • step 303 the protection signaling is forwarded to the second power station.
  • the protection signaling is forwarded to the second power station.
  • one piece of monitoring information is sent over a corresponding WAN when no protection signaling is transmitted, to monitor a communication status of the WAN.
  • a packet structure of the protection signaling sequentially includes synchronization information, type information, address information, data infor mation, and check information.
  • a transport protocol or transmission interface for the received protec tion signahng is different from that used for forwarding the protection signaling. As such, different physical connections may be matched.
  • receiving protection signaling from a first power station includes ⁇ re DCving, over an El channel, the protection signaling of the first power station that is transmitted by a multiplexer, where the E 1 channel includes a frame header and N sets of slots, and each set of slots corresponds to one set of protec tion signaling, where N is a positive integer greater than or equal to 4.
  • the transmission method further includes ; replicating the protection signaling in real time; and transmitting the protection signaling and the replicated protection signaling over two ports, respectively.
  • a transmission apparatus on a sending side will replicate received protection signaling, and transmit the pro tection signaling and the replicated protection signaling that are the same over two El ports, respectively.
  • a transmission apparatus on a receiving side identifies that a primary transmission unit thereof is faulty, it automatically switches to a backup transmission unit to receive the protection signahng, to avoid loss of the protection signaling.
  • the transmission method further includes : determining whether the number of pieces of consecutively received protection signaling that are the same reaches a preset threshold; and if a determining re sult is yes, determining, based on the information about the protection signaling, that the destination of the protection signaling is the second power station.
  • a same power station can implement point -to -multipoint protection signaling transmission, which saves costs.
  • the present invention further provides a power station for a power system, in cluding the foregoing transmission apparatus for one set of protection signahng of a power system.
  • the present invention further provides a power system, including a plurahty of power stations, where each power station has one transmission apparatus and implements point -to -multipoint transmission of one set of protection signaling through the transmission apparatus, and the transmission apparatus is the foregoing transmission apparatus.
  • a power system including a plurahty of power stations, where each power station has one transmission apparatus and implements point -to -multipoint transmission of one set of protection signaling through the transmission apparatus, and the transmission apparatus is the foregoing transmission apparatus.

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Abstract

The present invention provides a transmission apparatus and method for protection signaling of a power system, the power system including a plurahty of power stations that are connected to each other over a WAN, where each power station has one transmission apparatus, and the transmission apparatus includes: a first transmission unit configured to perform protection signaling transmission with a first power station; a second transmission unit configured to perform protection signaling transmission with a second power station; and a processor configured to receive protection signaling transmitted by the first transmission unit and determine whether to deliver the protection signaling or forward the protection signaling to the second transmission unit based on the protection signaling, and configured to receive protection signaling transmitted by the second transmission unit and determine whether to dehver the protection signaling or forward the protection signaling to the first transmission unit based on the protection signaling. The present invention can implement point-to-multipoint signaling transmission.

Description

TRANSMISSION APPARATUS AND METHOD FOR PROTECTION SIGNAL
ING OF POWER SYSTEM
TECHNICAL FIELD
The present invention relates to the field of power systems, and in particular, to a transmission apparatus and method for protection signaling of a power system.
BACKGROUND ART
A protective relay is an important device in a power system and is designed to detect the presence of a fault or an exception in the power system, and to transmit protection signaling to directly isolate and cut out the faulty part. As an interface device connected to the protective relay, a transmission apparatus for protection signaling is responsible for transmitting the protection signaling from the protec tive relay to a remote power station in a secure and timely manner, so as to im plement WAN protection of a high-voltage transmission line.
As shown in FIG. 1, in the prior art, it is assumed that there are three power sta tions, namely a power station 10, a power station 11, and a power station 12. Each power station includes a transmission apparatus for protection signaling, and the transmission apparatus for protection signaling is configured for protection sig naling transmission with a same power station. It is shown in FIG. 1 that each power station includes two transmission apparatuses for protection signaling, namely a transmission apparatus 101 for protection signaling, a transmission apparatus 102 for protection signaling, a transmission apparatus 103 for protec tion signahng, a transmission apparatus 104 for protection signaling, a trans mission apparatus 105 for protection signaling, and a transmission apparatus 106 for protection signaling. To enable protection signaling transmission between two power stations over a long distance, the two power stations that can communicate with each other perform protection signaling transmission over a WAN. As such, each transmission apparatus for protection signaling can perform protection sig- naling transmission only with a same transmission apparatus for protection sig naling of one power station, that is, point-to-point transmission. In other words, the transmission apparatus 101 for protection signaling in FIG. 1 can communi cate only with the transmission apparatus 103 for protection signaling. If the power station needs to perform protection signaling transmission with a second power station, one more transmission apparatus for protection signaling needs to be added to the power station. For example, the transmission apparatus 102 for protection signaling is added to the power station 10, to communicate with the transmission apparatus 105 for protection signaling in the power station 12, and the transmission apparatus 104 for protection signaling is added to the power station 11, to communicate with the transmission apparatus 106 for protection signaling in the power station 12. This greatly increases costs of the power sys tem.
SUMMARY OF THE INVENTION
In view of this, the present invention provides a transmission apparatus for pro tection signaling of a power system, the power system including a plurality of power stations that are connected to each other over a WAN, where each power station has one transmission apparatus, and the transmission apparatus in cludes: a first transmission unit configured to perform protection signaling trans mission with a first power station; a second transmission unit configured to perform protection signaling transmission with a second power station; and a processor configured to receive protection signaling transmitted by the first transmission unit and determine whether to deliver the protection signaling or forward the protection signaling to the second transmission unit based on the protection signaling, and configured to receive protection signaling transmitted by the second transmission unit and determine whether to dehver the protection signaling or forward the protection signahng to the first transmission unit based on the protection signaling.
The transmission apparatus for protection signahng may perform data transmis sion with two power stations respectively through two transmission units, which still implements point-to-point transmission for a same transmission unit, and still guarantees independence and security of protection signaling transmission. In addition, a fault that occurs in one transmission unit will not affect normal operation of the other transmission unit, which guarantees timeliness and relia bility of protection signahng transmission to the greatest extent on the basis of implementing point -to -multipoint transmission.
According to the transmission apparatus as described above, optionally, the transmission apparatus further includes : a set of interface cards through which the processor transmits the protection signaling to a relay protection apparatus of a power station where the processor is located.
According to the transmission apparatus as described above, optionally, the first transmission unit performs direct protection signaling transmission with the first power station over the WAN; and the second transmission unit performs direct protection signahng transmission with the second power station over the WAN.
According to the transmission apparatus as described above, optionally, if a con nection port of the WAN is a TDM port, each of the first transmission unit and the second transmission unit includes : a LID module for protection signaling transmission over one TDM port; or if the connection port of the WAN is a fiber-optic port, each of the first transmission unit and the second transmission unit includes : a LID module and a FOM module, where the FOM module is config- ured to perform optical signal modulation or optical signal encapsulation on the protection signaling, and the LID module is configured to pre-process the protec tion signaling.
According to the transmission apparatus as described above, optionally, the first transmission unit performs protection signaling transmission with the first power station via a multiplexer, and the second transmission unit performs protection signaling transmission with the second power station via the multiplexer.
According to the transmission apparatus as described above, optionally, the first transmission unit communicates directly with the first power station via the FOM module, and the second transmission unit communicates directly with the second power station via the FOM module.
According to the transmission apparatus as described above, optionally, the transmission apparatus further includes^ an alarm unit configured to transmit one piece of monitoring information when the transmission apparatus does not perform protection signaling trans mission, to monitor a communication status of the WAN and output an alarm signal.
According to the transmission apparatus as described above, optionally, a struc ture of a packet transmitted over the TDM port sequentially includes synchroni zation information, type information, address information, data information, and check information.
According to the transmission apparatus as described above, optionally, a transport protocol for the TDM port of the LID module of the first transmission unit is different from that for the TDM port of the LID module of the second transmission unit. According to the transmission apparatus as described above, optionally, the first transmission unit and the second transmission unit perform protection signaling transmission with a multiplexer over an E 1 channel, the multiplexer is configured to perform protection signahng transmission with the first power station and the second power station, the first transmission unit has an El port, and the second transmission unit has an El port.
According to the transmission apparatus as described above, optionally, when each of the first transmission unit and the second transmission unit includes a LID module, one of the first transmission unit and the second transmission unit serves as a primary transmission unit, the other serves as a backup transmission unit, and the backup transmission unit is capable of repheating the protection signaling transmitted by the primary transmission unit.
According to the transmission apparatus as described above, optionally, the El channel includes a frame header and N sets of slots, and each set of slots corre sponds to one set of protection signaling, where N is a positive integer greater than or equal to 4.
According to the transmission apparatus as described above, optionally, the pro tection signaling received by the transmission apparatus is a plurahty of pieces of consecutive protection signaling, information about each piece of protection sig nahng is the same, and the first transmission unit or the second transmission unit determines whether the number of pieces of consecutively received protection signaling that are the same is greater than or equal to a preset threshold, and if a determining result is yes, transmits the protection signaling to the processor.
The present invention further provides a power station for a power system, in cluding the transmission apparatus for protection signahng of a power system according to any one of the foregoing embodiments.
The present invention further provides a power system, including a plurahty of power stations that are connected to each other over a WAN, where each power station has one transmission apparatus, and the transmission apparatus is the transmission apparatus according to any one of the foregoing embodiments.
The present invention further provides a transmission method for protection signaling of a power system, the power system including a plurality of power sta tions that are connected to each other over a WAN, where each power station has one transmission apparatus for protection signaling, and the transmission method includes : receiving protection signaling from a first power station; determining, based on information about the protection signaling, that a destination of the protection signaling is a second power station; and forwarding the protection signaling to the second power station.
According to the transmission method as described above, optionally, the trans mission method further includes : transmitting one piece of monitoring information over a corresponding WAN when the transmission apparatus does not perform protection signaling transmission, to monitor a communication status of the WAN.
According to the transmission method as described above, optionally, a packet structure of the protection signahng sequentially includes synchronization in formation, type information, address information, data information, and check information.
According to the transmission method as described above, optionally, a transport protocol or transmission interface for the received protection signaling is different from that used for forwarding the protection signaling.
According to the transmission method as described above, optionally, after re ceiving protection signaling from a first power station, and before determining, based on information about the protection signaling, that a destination of the protection signaling is a second power station, the transmission method further includes : determining whether the number of pieces of consecutively received protection signaling that are the same reaches a preset threshold; and if a determining result is yes, determining, based on the information about the protection signaling, that the destination of the protection signaling is the second power station.
According to the transmission method as described above, optionally, receiving protection signaling from a first power station includes^ receiving, over an E 1 channel, the protection signaling of the first power station that is transmitted by a multiplexer, where the El channel includes a frame header and N sets of slots, and each set of slots corre sponds to one set of protection signaling, where N is a positive integer greater than or equal to 4.
According to the transmission method as described above, optionally, after re ceiving protection signaling from a first power station, the transmission method further includes : replicating the protection signaling in real time; and transmit ting the protection signaling and the replicated protection signaling over two ports, respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages of the present invention will be more apparent to those of ordinary skill in the art from the detailed description of preferred embodiments of the present invention with reference to the accompa nying drawings, in which:
FIG. 1 is a schematic structural diagram of a power system including a transmis sion apparatus for protection signaling in the prior art;
FIG. 2Ais a schematic structural diagram of a transmission apparatus for pro tection signaling of a power system according to an embodiment of the present invention;
FIG. 2B and FIG. 2C are schematic structural diagrams of direct transmission of protection signaling between a transmission apparatus for protection signaling of a power system and another power station according to the present invention;
FIG. 2D is a schematic structural diagram of transmission of protection signaling between a transmission apparatus for protection signaling of a power system and another power station via a multiplexer according to the present invention;
FIG. 2E is a schematic structural diagram of transmission of four sets of protec tion signaling at a time by a transmission apparatus for protection signaling of a power system according to the present invention;
FIG. 2F is a schematic structural diagram of backup of protection signaling by a transmission apparatus for protection signaling of a power system according to the present invention; and
FIG. 3 is a schematic flowchart of a transmission method for protection signaling of a power system according to an embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS In order to make the objectives, technical solutions, and advantages of the present invention more apparent, the present invention will be described in further detail by way of embodiments hereinafter.
A power system includes a plurality of power stations that are connected to each other over a WAN to perform protection signaling transmission. In the present invention, each power station has one transmission apparatus for protection sig¬ naling, and the transmission apparatus can perform protection signaling trans¬ mission in different directions. A specific structure of the transmission apparatus is as shown in FIG. 2 A. As shown in FIG. 2B, the power station 11 has one transmission apparatus 111, the power station 12 has one transmission apparatus 121, and the power station 10 has one transmission apparatus 20. Among the three power stations, the power station 11 and the power station 10 can perform protection signaling transmission with each other, and the power station 12 and the power station 10 can also perform protection signaling transmission with each other. As shown in FIG. 2B, the power station 10 may implement protection sig¬ naling transmission in the two directions D1 and D2. In addition, as shown in FIG. 2C, protection signaling to be transmitted between the power station 11 and the power station 12 may be forwarded by the power station 10, as shown by the ar¬ rows in FIG. 2C. The power station 11 may perform protection signaling trans¬ mission with the power station 10 in the direction D3, and may also perform pro¬ tection signaling transmission with the power station 12 in the direction D4. As such, the transmission apparatus in the present invention can implement point -to -multipoint transmission of protection signaling between the power sta¬ tions.
The present invention provides a transmission apparatus for protection signaling of a power system. The transmission apparatus can implement point -to -multipoint signaling transmission, that is, the transmission apparatus may perform protection signaling transmission in different transmission direc- tions.
FIG. 2Ais a schematic structural diagram of the transmission apparatus for pro tection signaling of a power system according to the present invention. The transmission apparatus 20 for protection signahng of a power system includes a first transmission unit 201, a second transmission unit 202, and a processor 203. The first transmission unit 201 is configured to perform protection signaling transmission with a first power station 11. The second transmission unit 202 is configured to perform protection signaling transmission with a second power sta tion 12. The processor 203 is configured to receive protection signaling transmit ted by the first transmission unit 201 and determine whether to deliver the pro tection signahng or forward the protection signahng to the second transmission unit 202 based on the protection signaling, and configured to receive protection signaling transmitted by the second transmission unit 202 and determine whether to dehver the protection signaling or forward the protection signaling to the first transmission unit 201 based on the protection signaling. A power station where the transmission apparatus is located is a power station 10.
As an exemplary description, as shown in FIG. 2B and FIG. 2C, a WAN is con nected between the first transmission unit 201 and the first power station 11, and the first transmission unit 201 can perform direct protection signaling transmis sion with the first power station 11 over the WAN, that is, physical connection between the first transmission unit 201 and the first power station 11 can guar antee protection signahng transmission therebetween. Similarly, a WAN is con nected between the second transmission unit 202 and the second power station 12, and the second transmission unit 202 can perform direct protection signahng transmission with the second power station 12 over the WAN. More specifically, the transmission apparatus 20 is connected to the transmission apparatus 111 in the first power station 11 and the transmission apparatus 121 in the second power station 12. As another exemplary description, as shown in FIG. 2D, both the first transmission unit 201 and the second transmission unit 202 may be connected to a multiplexer 21 (MUX), and the multiplexer 21 may be physically connected to and perform protection signaling transmission with a plurality of other power stations, that is, the first transmission unit 201 performs protection signahng transmission with the first power station via the multiplexer 21, and the second transmission unit 202 performs protection signahng transmission with the second power station via the multiplexer 21. Since many power stations in the prior art have multiplexers 21, and the multiplexers 21 are mainly used to combine a plu rality of channels of low-rate data and convert the combined low-rate data into higher-rate data for transmission. The transmission apparatus in this embodi ment can also be matched with the multiplexer 21, to be further well compatible with a hardware structure in the prior art.
The processor 203 is configured to receive the protection signaling transmitted by the first transmission unit 201 and determine whether to dehver the protection signaling or forward the protection signaling to the second transmission unit 202 based on the protection signaling, and configured to receive the protection sig naling transmitted by the second transmission unit 202 and determine whether to deliver the protection signaling or forward the protection signaling to the first transmission unit 201 based on the protection signaling. Information about the protection signaling includes an address of a sending end of the protection sig naling, namely a source address. Each source address has a pre-matched desti nation address. Therefore, the processor 203 determines, based on preset infor mation, whether the destination address is matched. If the destination address is matched, the processor 203 further determines, based on a DATA field in the protection signaling, whether to dehver or forward the protection signaling, that is, the processor 203 determines whether to send the protection signaling down stream or forward the protection signahng to the second transmission unit 202. As such, the protection signaling can be transmitted to the second power station 12 through the second transmission unit 202, to implement communication between the first power station 11 and the second power station 12, that is, implement a T-shaped communication architecture as shown by dotted lines in FIG. 2B. Simi larly, the protection signaling transmitted by the second power station 12 may also be forwarded to the first power station 11 through the transmission appa ratus for protection signaling. The processor herein may be at least one of the following apparatuses: a microprocessor, a digital signal processor (DSP), and a programmable logic array (FPGA).
The transmission apparatus for protection signaling may perform data transmis sion with two power stations respectively through two transmission units, which still implements point-to-point transmission for a same transmission unit, and still guarantees independence and security of protection signaling transmission.
In addition, a fault that occurs in one transmission unit will not affect normal operation of the other transmission unit, which guarantees timehness and relia bility of protection signaling transmission to the greatest extent on the basis of implementing point -to -multipoint transmission.
In this embodiment, if the WAN is a digital line, each of the first transmission unit 201 and the second transmission unit 202 may include a line interface digital (LID) module 2011, and the LID module 2011 performs protection signaling transmission over a time-division multiplexing (TDM) port. The LID module 2011 can pre-process the protection signaling into a packet structure as hsted in Table 1, to implement different digital transmission coding manners (for example, AMI coding and HDB3 coding), match different TDM ports, calculate a transmission bit error rate, monitor a transmission status of the line in real time, quickly switch to a backup line when a fault occurs, and reliably receive protection sig naling, and so on.
If the WAN between the two power stations is an optical fiber line, the first transmission unit 201 includes a LID module 2011 and a fiber-optic modem (FOM) module 2012, and the second transmission unit 202 may also include a LID mod ule 2011 and a FOM module 2012. For example, after receiving the protection signaling, the FOM module 2012 of the first transmission unit 201 performs op tical signal modulation on the protection signaling and transmits the modulated protection signaling to the LID module 2011 of the first transmission unit 201 for pre-processing, and the LID module 2011 of the first transmission unit 201 fur ther transmits the pre-processed protection signaling to the processor 203. If the processor 203 identifies, based on the protection signaling, that the protection signaling should be forwarded to the second power station 12, the processor 203 transmits the protection signaling to the LID module 2011 of the second trans mission unit 202, the LID module 2011 of the second transmission unit 202 pre-processes the protection signaling, the FOM module 2012 of the second transmission unit 202 performs optical signal encapsulation on the pre-processed protection signaling, and the FOM module 2012 of the second transmission unit 202 transmits the pre-processed protection signaling to the second power station 12 over an optical port thereof (not shown in the figure). The port of the FOM module 2012 may be directly connected to the second power station through an optical fiber.
Optionally, protocols used by the TDM ports of the two transmission units may be the same or different. As an exemplary description, if the used protocols are the same, structures of the two transmission units are the same. As an exemplary description, the used protocols are different, for example, one TDM port uses a 64 Kbps X.21 port or G.703.1 port, and the other TDM port uses a 2 Mbps G.703.6 port or fiber-optic port. As such, different protocols adapt to transmission hnes with different requirements. For example, if the WAN corresponding to one transmission unit is an optical fiber line, and the WAN corresponding to the other transmission unit is a digital line, the transmission unit corresponding to the op tical fiber line may have both the LID module 2011 and the FOM module 2012, and the transmission unit corresponding to the digital line may have one LID module 2011, which may be specifically selected according to actual requirements, that is, relevant hardware configuration and software configuration may be im¬ plemented based on actual physical connection.
A structure of a packet transmitted over the TDM port sequentially includes synchronization information (SYNC), type information (TYPE), address infor¬ mation (ADR), data information (DATA), and check information (CRC). For de¬ tails, see Table 1. SYNC denotes a packet synchronization signal, TYPE denotes a type of the packet, the address information includes a source address of the packet, and the check information is used for a consistency check. After receiving the protection signahng, the transmission unit first performs a consistency check. During the consistency check, whether a check value included in the check in¬ formation is correct is first detected. If the check value is correct, whether the address information matches a preset address of a power station that can com¬ municate with the transmission unit is determined. If the address information matches the preset address, the consistency check succeeds, then the protection signaling is decoded, and the decoded protection signaling is sent downstream or forwarded. How to decode the protection signaling belongs to the prior art, and is not repeated herein. If the consistency check fails, the protection signaling is discarded. As an exemplary description, a delivery and forwarding process is de¬ scribed as follows: (a) after receiving protection signaling, the transmission ap¬ paratus 20 determines a start location of a packet of the protection signaling based on SYNC, and if the determining fails, the packet is discarded, or if the determining succeeds, step (b) is performed; (b) whether a type of the packet is correct is determined based on TYPE, and if the type is incorrect, the packet is discarded, or if the type is correct, step (c) is performed; (c) whether the CRC check succeeds is determined, and if the check fails, the packet is discarded, or if the check succeeds, step (d) is performed; (d) whether the ADR matches a pre-configured destination address is determined, and if the ADR does not match the pre-configured destination address, the packet is discarded, or if the ADR matches the pre-configured destination address, step (e) is performed; and (e) DATA is checked, where each piece of DATA has a pre-configured static route, and the processor 203 determines, based on the static route, whether to deliver or forward the protection signaling.
A time for transmitting the protection signaling is very critical, and has been specified in the standard IEC60834-1. To guarantee timely transmission of the protection signaling, a transmission speed of the TDM port may be selected as 2 Mbps. As such, a delay caused by forwarding may be very small, for example, less than 0.1 ms.
Table 1
Figure imgf000017_0001
As shown in FIG. 2A, the transmission apparatus 20 further includes a set of in terface cards 204, and the processor 203 sends the protection signaling down stream through the interface cards 204. Sending the protection signaling down stream herein refers to transmitting the protection signaling to a relay protection apparatus of a same power station. FIG. 2 shows four interface cards 204, and the number of interface cards 204 may be adjusted according to actual requirements. Four sets of protection signahng may be transmitted through each interface card 204 at a time.
Optionally, the transmission apparatus 20 further includes an alarm unit 205 configured to monitor an operation status of the transmission apparatus. Since the transmission apparatus itself is a transceiver apparatus, whether the trans mission apparatus performs protection signaling transmission may be learned, and when the transmission apparatus does not perform protection signaling transmission, the transmission apparatus will continuously transmit monitoring information, to monitor a status of a communication line of the WAN. Optionally, the alarm unit 205 may also give an alarm through self- detection, for example, may give an alarm when transmission fails or power is insufficient.
Optionally, the transmission apparatus 20 further includes a power module 206, and the power module 206 is configured to provide power.
When there is a multiplexer 21, both the first transmission unit 201 and the sec ond transmission unit 202 may be connected to the multiplexer 21 over an El channel and perform protection signaling transmission via the multiplexer 21, and the multiplexer 21 is configured to perform protection signahng transmission with the first power station 11 and the second power station 12. Each transmis sion unit has one El port, and over the two El ports, protection signahng trans mission in two directions is implemented. In practical application, each El port may support transmission of two signaling sets at a time, and each signaling set may include four or eight pieces of signahng. Such a technology is referred to as a channelized El (CEl) technology. As such, the transmission apparatus including two transmission units have four El ports, and via the multiplexer 21, may im plement protection signaling transmission in four directions. As shown in FIG. 2E, the CEl technology with which the transmission apparatus can perform protec tion signahng transmission in four directions A, B, C, and D at a time uses pulse code modulation (PCM) for decoding or encoding.
For a frame structure of the El channel, a transmission speed thereof is 2.048 Mbps, 8 bits form one slot (Ts), and 32 slots form one frame (F). The 32 slots may be divided into one frame header and a plurality of sets of slots, for example, N sets of slots, and each set of slots corresponds to one set of protection signaling, where N is a positive integer greater than or equal to 4. As an exemplary descrip tion, when N = 4, slots 1 to 5 are allocated to the first set of protection signaling, slots 6 to 10 are allocated to the second set of protection signaling, slots 11 to 31 are reserved for a subsequent extended function, for example, five slots fall into one set. Correspondingly, in a frame structure of the El channel corresponding to the other transmission unit, slots 1 to 5 are allocated to the third set of protection signaling, slots 6 to 10 are allocated to the fourth set of protection signaling, and slots 11 to 31 are reserved for a subsequent extended function. Specifically, Table 2 and Table 3 respectively list a frame structure of the El channel corresponding to the first transmission unit 201 and a frame structure of the El channel corre sponding to the second transmission unit 202. A frame alignment signal (FAS) denotes a frame header, which is located in the slot 0. A structure of each piece of protection signaling may be as listed in Table 1. Table 2
Figure imgf000019_0001
Table 3
Figure imgf000019_0002
After receiving protection signaling over the El channel, the transmission appa- ratus parses the protection signaling, for example, performs a consistency check after removing a frame header. A manner of the consistency check is the same as that in the foregoing embodiment, and will not be repeated herein.
As an exemplary description, when the transmission units need to perform pro- tection signaling transmission over the E 1 channel and each of the first trans mission unit and the second transmission unit includes a LID module, the LID module of one of the two transmission units may serve as a backup transmission unit, and the LID module of the other transmission unit may serve as a primary transmission unit. For example, the first transmission unit 201 serves as the primary transmission unit, and has one El port. The second transmission unit 202 serves as the backup transmission unit, also has one El port, and can repli cate the protection signahng transmitted by the first transmission unit 201, so that the protection signaling and the rephcated protection signaling that are the same are simultaneously transmitted over the two El ports, respectively. As an exemplary description, a transmission apparatus on a sending side will replicate received protection signaling, and transmit the protection signaling and the rep licated protection signaling that are the same over two El ports, respectively. Af ter a transmission apparatus on a receiving side identifies that a primary trans mission unit thereof is faulty, it automatically switches to a backup transmission unit to receive the protection signahng, to avoid loss of the protection signaling. As such, when the transmission apparatus that receives the protection signahng identifies that a port or transmission line in the primary transmission unit of the transmission apparatus that transmits the protection signaling is faulty, it au tomatically switches to the backup transmission unit to receive the protection signaling, which can guarantee normal transmission and reception of the protec tion signaling. In addition, two different sets of protection signaling may be transmitted over each El channel, that is, the transmission apparatus can sup port both one-to-many transmission and 1 + 1 hne backup transmission. As shown in FIG. 2F, the transmission apparatus can perform protection signaling trans mission in both directions A and B at a time, and back up protection signaling in both directions A and B, where the dotted line denotes the backup line.
Optionally, the protection signaling received by the transmission apparatus is a plurality of pieces of consecutive protection signaling, information about each piece of protection signaling is the same, and the first transmission unit 201 or the second transmission unit 202 determines whether the number of pieces of consecutively received protection signaling that are the same reaches a preset threshold, and if a determining result is yes, transmits the protection signaling to the processor 203. To ensure that the protection signaling is not lost, a plurality of pieces of same protection signaling are usually sent consecutively. After receiving the plurahty of pieces of same protection signaling, the first transmission unit 201 or the second transmission unit 202 determines, based on the number of pieces of received same protection signaling, whether to transmit the protection signahng. When the number of pieces of received same protection signaling reaches a preset threshold, it indicates that the protection signaling may be securely received.
The present invention further provides a transmission method for protection signaling of a power system. The power system includes a plurality of power sta tions. The power stations are connected to each other over a WAN. Each power station has one transmission apparatus for protection signahng.
As shown in FIG. 3, the transmission method includes the following steps.
In step 301, protection signaling from a first power station is received.
Specifically, the protection signaling transmitted by the first power station may be directly received over a physically connected WAN or via a multiplexer.
If the protection signaling is an optical signal, after the protection signahng in the form of the optical signal is received, the optical signal is processed, and how to process the optical signal belongs to the prior art, and is not repeated herein.
In step 302, a destination of the protection signahng is determined as a second power station based on information about the protection signaling.
The protection signaling includes a source address. Whether a pre-configured destination address is matched is determined based on the source address, and whether the protection signaling needs to be sent downstream or forwarded to the second power station is determined based on the protection signaling.
In step 303, the protection signaling is forwarded to the second power station.
If the matched destination address is the second power station, the protection signaling is forwarded to the second power station.
Optionally, one piece of monitoring information is sent over a corresponding WAN when no protection signaling is transmitted, to monitor a communication status of the WAN.
Optionally, a packet structure of the protection signaling sequentially includes synchronization information, type information, address information, data infor mation, and check information.
Optionally, a transport protocol or transmission interface for the received protec tion signahng is different from that used for forwarding the protection signaling. As such, different physical connections may be matched.
Optionally, receiving protection signaling from a first power station includes^ re ceiving, over an El channel, the protection signaling of the first power station that is transmitted by a multiplexer, where the E 1 channel includes a frame header and N sets of slots, and each set of slots corresponds to one set of protec tion signaling, where N is a positive integer greater than or equal to 4.
Optionally, after receiving protection signaling from a first power station, the transmission method further includes ; replicating the protection signaling in real time; and transmitting the protection signaling and the replicated protection signaling over two ports, respectively. As an exemplary description, a transmission apparatus on a sending side will replicate received protection signaling, and transmit the pro tection signaling and the replicated protection signaling that are the same over two El ports, respectively. After a transmission apparatus on a receiving side identifies that a primary transmission unit thereof is faulty, it automatically switches to a backup transmission unit to receive the protection signahng, to avoid loss of the protection signaling.
Optionally, after receiving protection signaling from a first power station, and before determining, based on information about the protection signaling, that a destination of the protection signaling is a second power station, the transmission method further includes : determining whether the number of pieces of consecutively received protection signaling that are the same reaches a preset threshold; and if a determining re sult is yes, determining, based on the information about the protection signaling, that the destination of the protection signaling is the second power station.
A specific process of the transmission method is the same as that in the foregoing embodiment, and is not repeated herein.
According to the transmission method for protection signahng of a power system, a same power station can implement point -to -multipoint protection signaling transmission, which saves costs.
The present invention further provides a power station for a power system, in cluding the foregoing transmission apparatus for one set of protection signahng of a power system.
The present invention further provides a power system, including a plurahty of power stations, where each power station has one transmission apparatus and implements point -to -multipoint transmission of one set of protection signaling through the transmission apparatus, and the transmission apparatus is the foregoing transmission apparatus. The above description is merely illustrative of the preferred embodiments of the present invention and is not intended to limit the present invention. Any modifi¬ cations, equivalent substitutions, improvements, and the like made within the spirit and principles of the present invention shall fall within the scope of protec¬ tion of the present invention.

Claims

1. A transmission apparatus for protection signaling of a power system, the power system comprising a plurality of power stations that are connected to each other over a wide area network (WAN), wherein each power station has one transmission apparatus, and the transmission apparatus comprises: a first transmission unit configured to perform protection signaling transmission with a first power station; a second transmission unit configured to perform protection signal¬ ing transmission with a second power station; and a processor configured to receive protection signaling transmitted by the first transmission unit and determine whether to deliver the protection signaling or forward the protection signaling to the second transmission unit based on the protection signaling, and configured to receive protection signaling transmitted by the second transmission unit and determine whether to deliver the protection signaling or forward the protection sig¬ naling to the first transmission unit based on the protection signaling.
2. The transmission apparatus as claimed in claim 1, wherein the transmis¬ sion apparatus further comprises: a set of interface cards through which the processor transmits the protection signahng to a relay protection apparatus of a power station where the processor is located.
3. The transmission apparatus as claimed in claim 1 or 2, wherein the first transmission unit performs direct protection signahng transmission with the first power station over the WAN; and the second transmission unit performs direct protection signaling transmission with the second power station over the WAN.
4. The transmission apparatus as claimed in any one of claims 1 - 3, wherein if a connection port of the WAN is a TDM port, each of the first transmission unit and the second transmission unit comprises : a LID module for protection signal ing transmission over one TDM port; or if the connection port of the WAN is a fiber-optic port, each of the first transmission unit and the second transmission unit comprises : a LID module and a FOM module, wherein the FOM module is configured to perform optical signal modulation or optical signal encapsulation on the protection signaling, and the LID module is configured to pre-process the protection signaling.
5. The transmission apparatus as claimed in claim 4, wherein the first transmission unit performs protection signaling transmission with the first power station via a multiplexer, and the second transmission unit performs protection signaling transmission with the second power station via the multiplexer.
6. The transmission apparatus as claimed in claim 4 or 5, wherein the first transmission unit communicates directly with the first power station via the FOM module, and the second transmission unit communicates directly with the second power station via the FOM module.
7. The transmission apparatus as claimed in any one of claims 1 - 6, further comprising: an alarm unit configured to transmit one piece of monitoring information when the transmission apparatus does not perform protection signaling trans mission, to monitor a communication status of the WAN and output an alarm signal.
8. The transmission apparatus as claimed in an one of claims 4 - 7, wherein a structure of a packet transmitted over the TDM port sequentially comprises synchronization information, type information, address information, data infor- mation, and check information.
9. The transmission apparatus as claimed in any one of claims 4 - 8, wherein a transport protocol for the TDM port of the LID module of the first transmission unit is different from that for the TDM port of the LID module of the second transmission unit.
10. The transmission apparatus as claimed in any one of claims 1 - 9, wherein the first transmission unit and the second transmission unit perform protection signaling transmission with a multiplexer over an E 1 channel, the multiplexer is configured to perform protection signaling transmission with the first power sta tion and the second power station, the first transmission unit has an El port, and the second transmission unit has an El port.
11. The transmission apparatus as claimed in claim 10, wherein when each of the first transmission unit and the second transmission unit comprises a LID module, one of the first transmission unit and the second transmission unit serves as a primary transmission unit, the other serves as a backup transmission unit, and the backup transmission unit is capable of replicating the protection signal ing transmitted by the primary transmission unit.
12. The transmission apparatus as claimed in any one of claims 8 - 11, wherein the E 1 channel comprises a frame header and N sets of slots, and each set of slots corresponds to one set of protection signaling, wherein N is a positive integer greater than or equal to 4.
13. The transmission apparatus as claimed in any one of claims 1 - 12, wherein the protection signaling received by the transmission apparatus is a plurality of pieces of consecutive protection signaling, information about each piece of protec tion signaling is the same, and the first transmission unit or the second trans- mission unit determines whether the number of pieces of consecutively received protection signaling that are the same is greater than or equal to a preset threshold, and if a determining result is yes, transmits the protection signahng to the processor.
14. A power station for a power system, comprising the transmission apparatus for protection signaling of a power system as claimed in any one of claims 1 - 13.
15. A power system, comprising a plurality of power stations that are connected to each other over a WAN, wherein each power station has one transmission ap paratus, and the transmission apparatus is the transmission apparatus as claimed in any one of claims 1 - 13.
16. A transmission method for protection signaling of a power system, the power system comprising a plurality of power stations that are connected to each other over a WAN, wherein each power station has one transmission apparatus for protection signaling, and the transmission method comprises : receiving protection signaling from a first power station; determining, based on information about the protection signaling, that a destination of the protection signaling is a second power station; and forwarding the protection signaling to the second power station.
17. The transmission method as claimed in claim 16, further comprising: transmitting one piece of monitoring information over a corresponding
WAN when the transmission apparatus does not perform protection signaling transmission, to monitor a communication status of the WAN.
18. The transmission method as claimed in claim 16 or 17, wherein a packet structure of the protection signaling sequentially comprises synchronization in formation, type information, address information, data information, and check information.
19. The transmission method as claimed in any one of claims 16 - 18, wherein a transport protocol or transmission interface for the received protection signaling is different from that used for forwarding the protection signaling.
20. The transmission method as claimed in any one of claims 16 - 19, wherein after receiving protection signaling from a first power station, and before deter mining, based on information about the protection signaling, that a destination of the protection signaling is a second power station, the transmission method fur ther comprises : determining whether the number of pieces of consecutively received protection signaling that are the same reaches a preset threshold; and if a determining result is yes, determining, based on the information about the protection signaling, that the destination of the protection sig naling is the second power station.
21. The transmission method as claimed in any one of claims 16 - 20, wherein receiving protection signahng from a first power station comprises^ receiving, over an El channel, the protection signahng of the first power station that is trans mitted by a multiplexer, wherein the E 1 channel comprises a frame header and N sets of slots, and each set of slots corresponds to one set of protection signaling, wherein N is a positive integer greater than or equal to 4.
22. The transmission method as claimed in claim 21, wherein after receiving protection signahng from a first power station, the transmission method further comprises : replicating the protection signaling in real time; and transmitting the protection signaling and the replicated protection signaling over two ports, respectively.
PCT/EP2022/063504 2021-05-21 2022-05-19 Transmission apparatus and method for protection signaling of power system WO2022243401A1 (en)

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