KR100716357B1 - Protection relay and information communication method - Google Patents

Abstract

The present invention discloses a method of protecting a protective relay and a power system using a plurality of user selectable communication protocols over a plurality of communication ports. The relay may support multiple communication protocols through a single communication port, and may support simultaneous formatting and communication through multiple communication ports using different protocols. Protection control is enhanced by supporting a full array of communication protocols on each relay.

Description

MULTIPLE COMMUNICATIONS PROTOCOLS IN A PROTECTIVE RELAY}             

The present invention relates generally to the protection of digital protective relays and power distribution systems. In particular, the present invention relates to a digital protection relay having a communication capability.

Intelligent protection relays are known that use digital microprocessors to provide protection control of power distribution systems. Digital protection relays with communication capabilities are also known. However, typically the communication capability is relatively limited and for communicating over a Universal Asynchronous Receiver Transmitter (UART) data link layer with RS485, RS232 or other fiber optic physical layer interfaces, for example Modbus RTU or ASCII. Include application layer protocols such as: A typical digital protection relay with communication capability only supports one application layer communication protocol even when it includes multiple communication ports.

U. S. Patent No. 5,680, 324 discloses a communication processor for a power substation. The communication processor comprises an electronic network having 17 individual communication ports, four orthogonal UART devices each supporting four ports, and a microprocessor for processing and controlling the flow of data under the control of stored control programs, command settings, and command logic. It includes a system. Relays, meters or other intelligent electronic devices are connected to some of the ports and a remote terminal unit, local computer or modem is connected to the master ports. The communication processor has the ability to communicate with various port devices via the ASCII communication format. The processor may support simultaneous communication with multiple devices and users. However, the processor is a centralized communication device that is separate and distinct from protection relays, meters, and other port devices. Thus, U. S. Patent No. 5,680, 324 does not focus on the communication capabilities of relays or other port devices.

In order to improve the usefulness of the digital protection relay and provide more comprehensive protection control of the power distribution system, it would be desirable to improve the communication capability of the digital protection relay. In particular, protection relays that support multiple communication protocols and multiple communication network profiles would be desirable. It would also be desirable to have a protection relay that simultaneously communicates on different types of communication networks, such as well-known LANs, wide area networks (WANs), and the Internet, and that sequentially communicates over different protocols over the same communication port. It would also be more desirable for a relay to allow the user to select a protocol and / or communication profile. Known protective relays do not fully address these needs.

summary

The present invention provides a connection for operatively connecting a relay to an electrical distribution system, at least one communication port for communicating relay information over a communication network, monitoring the electrical distribution system via the connection, and controlling protection for the electrical distribution system. By providing a protection relay comprising a processing circuit for generating a relay information to be communicated on a communication network, and formatting the relay information into one of a plurality of communication protocols, to solve the above problems, and to achieve additional advantages do. The communication network may be a LAN, WAN, Internet or other suitable network. The communication protocol may be selected by the user, and the relay may communicate simultaneously through separate communication ports using different communication protocols, and may sequentially communicate through a single communication port.

The present invention can provide greatly improved protection control of the power distribution system by greatly improving the communication capability of the relay.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention, its features, and advantages will be more clearly understood by referring to the following description and the accompanying drawings, in which like reference characters designate the same components.

1 is a diagram illustrating communication protocols supported in some known industrial communication systems.

2 is a diagram illustrating communication protocols supported by some known Profibus based communication systems.

3 is a diagram illustrating communication protocols supported by some known Ethernet-based communication systems.

4 is a diagram illustrating support of the present invention for seven layers of communication protocols.

5 is a block diagram of a relay according to an embodiment of the present invention supporting the communication profile of FIG.

6 is a diagram illustrating exemplary classification of communication classes and subclasses.

7 is a diagram illustrating an exemplary protocol layering in a relay.

FIG. 8 is a diagram illustrating high level data flow inside and outside the communication subsystem of the relay of FIG. 5.

9 is a detailed view of the internal processing components of the relay of FIG.

1, a protocol stack or communication profile of a known industrial communication system is shown. Such known systems include application layer protocols such as Modbus or DNP 3.0, data link protocols such as UART (using 8 bits, 1 stop bit, no parity bits), RS232, RS485 or fiber optics. It supports physical layer protocols such as communication. As shown in FIG. 1, the remaining layers (presentation layer, session layer, transport layer, network layer) of the ISO 7 layer OSI model for a typical communication system are not required or implemented in a typical industrial communication system.

2 is a diagram illustrating a communication profile of a Profibus based communication system. This known system supports the application layer protocol in the form of FMS or DP, the data link layer protocol FDL achieved by the chip set of Siemens Corporation, and the physical layer protocol RS485. The Profibus system also supports the LLI protocol (for presentation and session layers) and the FMA protocol (for transport and network layers).

3 shows a protocol stack of a conventional Ethernet communication system (according to the IEEE 802.3 standard). The protocol stack is based on application layer protocols such as Modbus or DNP 3.0, data link layer protocols according to the IEEE 802.2 standard (also known as CSMA / CD), and IEEE 802.3 standard (also known as 10BaseT / 5/2 / FL). It includes a physical layer protocol. The transport and network layers are supported by the TCP / IP or UDP protocol, and the presentation and session layers are not implemented or required in Ethernet based systems.

It will be appreciated that none of the examples shown in FIGS. 1-3 support individual communication formats at all layers of the Industrial Standards Organization (ISO) open systems interconnect (OSI) 7 layer network model. 4, a protocol stack of a relay according to an embodiment of the present invention is shown. The protocol stack includes application layer format MMS, presentation layer format RFC1006-expression, session layer format RFC1006-session, transport layer format TP4, network layer format CLNP, data link layer format IEEE 802.2 and physical layer format IEEE 802.3. By supporting all seven layers of the ISO / OSI model, the communication possibilities of each individual protection relay and the protection control of the networked relays are greatly improved.

Referring to FIG. 5, shown is a block diagram of an example relay suitable for communicating over any one or more of the protocols of FIG. 4. The relay 10 includes a connection 12 operatively connecting the relay to the electrical distribution system 14. The relay 10 further includes one or more communication ports 16 for communicating relay information (eg, monitored current and voltage parameters, or other power system data) on the communication network 18. Although communication network 18 is preferably a peer-to-peer communication network, it will be appreciated that other suitable communication networks may be used. The relay 10 monitors various parameters derived from the electrical distribution system via the connection 12 and (eg, operates a circuit breaker or performs some other protective action). And a microprocessor 20 suitably programmed to provide protection control of 14 and to generate and format relay information to be communicated on the communication network 18. The microprocessor formats the relay information with any one of the plurality of communication protocols identified in FIG. 4.

The microprocessor is suitably further programmed to provide simultaneous communication over the same or different communication channels, i.e., the microprocessor 20 is capable of: 1) a plurality of data for selection by the user for data transmission via a single communication port. Format, and 2) identify and distinguish the format format of the received data, thereby receiving data in multiple data formats through a single communication port, and simultaneously transmitting data in the same or multiple data formats through multiple communication ports. Can send and receive.

A further advantage of the present invention is achieved by the support of the microprocessor 20 for the TCP / IP protocol. Since this well-known protocol is used for data transmission over the Internet, the support of the TCP / IP protocol at each relay allows any relay associated with the power distribution system to be accessed from any device capable of internet communication. As a result, power system data can be collected remotely from any or all of the protection relays associated with the power distribution system. Moreover, the setting and operation of each relay can be adjusted remotely from any internet communication device. That is, communication network 18 in FIG. 5 includes the Internet. For the integrity of the communication network, a security firewall (e.g., a password protection authentication scheme that is well known for the most part) may be implemented within the relay processor to prevent unauthorized changes to relay configuration and operation. .

Port 16 of the relay of FIG. 5 may be configured to independently and simultaneously support different communication protocols, stacks, and physical layer interfaces such as Ethernet or RS485 via processor 20. The processor 20 manages the communication port 16 and also " virtualizes " various transport mechanisms (e.g., UDP datagram sockets, TCP sockets) over Ethernet so that they are physical ports. It can be allowed to operate an asynchronous serial protocol over Ethernet by being treated as.

According to one embodiment conceptually illustrated in FIG. 6, relay communication may be implemented using two base classes-subclasses of COM_Port and COM_Application. In addition, one of each of these classes is selected by the processor 20 to implement the protocol.

The COM_Port subclass defines the physical layer requirements for specific serial hardware, or "virtual" serial ports (such as TCP or UDP host ports). In general, the interface to the COM_Port class corresponds to a standard known as RFC1006 and is described in a document entitled "ISO Transport Service on Top of the TCP", the entire contents of which are incorporated by reference. This document defines a standard connection-oriented interface to support the TCP / IP protocol. It also supports connectionless through mode setting instructions from the processor 20. In a "virtual" serial port, there may be several protocol layers implemented in COM_Port (e.g. TCP / IP / Ethernet as in RFC1006), but these protocol layers will be hidden so that the object To a simple serial port.

The COM_Application subclass defines a higher level of specific protocols. Depending on the particular protocol to be implemented, there may be several operating system interface (OSI) layers defined in the COM_Application object.

Preferably, the COM_Application and COM_Port classes are written in software in a manner that allows any application to be used on any port. Alternatively, a given protocol type may be provided as a separate communication library with its own protocol stack and thus implemented as a COM_Application class that does not connect to a port.

In general, the configuration and initialization of the physical port 16 is performed through the COM_Port class. Each COM_Port object attaches itself to the COM_Application object whenever a protocol is specified for the port (if configured). In that process, each COM_Port object identifies itself to the COM_Application object, thereby making it a cross reference between the two objects. Thus, the COM_Application object can take advantage of the features in the COM_Port class and vice versa.

As shown in Fig. 6, the COM_Port communication class includes the following subclasses: COM_Com1Port (communicating on COM1 RS485); COM_Com2Port (communicating on COM2 RS485); COM_UdpPort (communicating using UDP sockets); COM_TcpPort (communicating using a TCP socket, as described in RFC1006); Contains COM_RS232Port (communicating on an RS232 serial port). The COM_Application class consists of the following subclasses: COM_ModbusApplication (Modbus protocol); COM_DnpApplication (DNP Protocol); Contains COM_MmsApplication (MMS protocol).

7 illustrates the protocol layering in the relay, ie the layers of the COM_Application class. In the case of a relay 10 having two physical ports 16, the microprocessor 20 may configure the port 16 as an Ethernet port or a physical serial port, and the microprocessor 20 may also configure a relay configured physical Port 16 can be configured to communicate in accordance with MMS, Modbus, or DNP 3.0. It will be appreciated that the present invention is not limited to the implementation of the particular communication protocol shown in FIG. 7, and the principles of the present invention may be applied to other communication protocols.

Referring to FIG. 8, the high level data flow in and out of the communication subsystem of the relay (within or under the control of microprocessor 20) of FIG. 5 is illustratively shown. The processes in this figure are further decomposed in the section corresponding to the base classes COM_Application and COM_Port, and further decomposed in the section for the subclass. In the data flow diagram of FIG. 8, the "event signal" flow may include the following specific signals: Rx frame signal, Tx execution signal, timeout signal and access signal.

Referring to FIG. 9, the internal processing components of the relay of FIG. 5 are shown in more detail. The relay receives current and transformer samples (eg, 64 samples per power system cycle) from the current transformer and transformer input 22. The sample is processed in a digital signal processor 24 that performs basic calculations of power system parameters such as phasor, frequency, RMS values, etc. and performs acquisition and calibration of current and voltage signals. DSP 24 exchanges various data, such as DSP firmware, configuration data, samples and maintenance data, oscillography samples, and the like with microprocessor 20a (which in one implementation may be a PowerPC 860 microprocessor). . Microprocessor 20a provides protection and control of associated power systems, programmable logic, metering, event recording, oscillography and other suitable functions.

Microprocessor 20a provides digital output data to digital output 26 and receives digital input data from digital input 28. In addition, the microprocessor 20a receives a synchronization signal, such as a signal according to the known IRIG-B standard, from the time code generator 30 and externally via an RS485 or Ethernet communication port 16 using Modbus or DNP protocols. It may communicate with a personal computer or a supervisory control and data acquisition (SCADA) system 32 and may also communicate with a remote input / output module 34 via an RS485 port 16. The remote input / output module may be another protective relay connected to the communication network.

The relay 20 further includes a user interface panel processor 36 for receiving user data via the input keypad 38 to provide user data to the microprocessor 20a. The user interface panel processor 36 also receives the display and LED control data from the microprocessor 20a and displays this data to the user via the LED 39 and alphanumeric display 40.

While the foregoing detailed description provides a number of details, it is merely illustrative and is not intended to limit the scope of the invention in any way. Those skilled in the art will be able to make modifications to the specific embodiments disclosed above in various ways without departing from the scope and spirit of the invention as defined by the following claims and their legal equivalents.

Claims (24)

In protective relay, A connection for operatively connecting said relay to an electrical distribution system, At least one communication port for communicating relay information over a communication network, Processing circuitry for monitoring the electrical distribution system via the connection, providing protection control to the electrical distribution system, generating relay information to be communicated on the communication network, and formatting the relay information with one of a plurality of communication protocols. (including processing circuitry) Protection relay. The method of claim 1, The communication network includes a local area network (LAN) and a wide area network (WAN), wherein one of the communication protocols is a TCP / IP protocol. delete delete delete delete delete The method of claim 1, And the processing circuit exchanges relay information through the at least one communication port using a different communication protocol. delete A method of communicating information from a protection relay to a remote device on a communication network, the method comprising: Generating relay information in the protection relay; Formatting the relay information according to one of a plurality of user-selectable communication protocols;  Transmitting the relay information on the communication network through one or more communication ports of the protection relay in a protocol selected by the user. Information communication method. The method of claim 10, Receiving relay information from the communication network through the one or more communication ports; Determining a communication protocol of the received relay information; Acting on the received relay information further; Information communication method. The method of claim 10, And wherein said plurality of user selectable communication protocols comprises a TCP / IP protocol. delete delete delete delete delete In the protection relay, A connection disposed on the protective relay and for allowing the relay to be operatively connected to an electrical distribution system; At least one communication port connectable to a digital communication network, the digital communication network communicating relay information on the digital communication network; Included within the protection relay, processing circuitry is programmed to monitor and provide protection control for the electrical distribution system via the connection, generate the relay information, and format the relay information into one of a plurality of communication protocols. Protection relay. delete delete delete A method of communicating information from a protection relay to a remote device via a communication network, the method comprising: Generating relay information indicative of one or more parameters of an electrical distribution system associated with the protection relay; Formatting the relay information according to one of a plurality of communication protocols; Transmitting the relay information through at least one of a plurality of communication ports connected to the communication network; Information communication method. The method of claim 22, And said transmitting step is performed by simultaneously transmitting relay information through at least two of said plurality of communication ports. The method of claim 23, The relay information transmitted through the first one of the at least two communication ports has a first data format corresponding to a first communication protocol, and the relay information transmitted through the second one of the communication ports is delimited. 2 An information communication method having a second data format corresponding to a communication protocol.

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