WO2010081798A1 - Communication method and system - Google Patents
Communication method and system Download PDFInfo
- Publication number
- WO2010081798A1 WO2010081798A1 PCT/EP2010/050273 EP2010050273W WO2010081798A1 WO 2010081798 A1 WO2010081798 A1 WO 2010081798A1 EP 2010050273 W EP2010050273 W EP 2010050273W WO 2010081798 A1 WO2010081798 A1 WO 2010081798A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- node
- data packets
- communication
- channel
- data
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
-
- 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
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/54—Systems for transmission via power distribution lines
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L43/00—Arrangements for monitoring or testing data switching networks
- H04L43/06—Generation of reports
- H04L43/062—Generation of reports related to network traffic
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L43/00—Arrangements for monitoring or testing data switching networks
- H04L43/08—Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters
- H04L43/0805—Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters by checking availability
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L43/00—Arrangements for monitoring or testing data switching networks
- H04L43/08—Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters
- H04L43/0852—Delays
- H04L43/0864—Round trip delays
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2203/00—Indexing scheme relating to line transmission systems
- H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
- H04B2203/5429—Applications for powerline communications
- H04B2203/5458—Monitor sensor; Alarm systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
- H04J3/0658—Clock or time synchronisation among packet nodes
- H04J3/0661—Clock or time synchronisation among packet nodes using timestamps
- H04J3/0667—Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L43/00—Arrangements for monitoring or testing data switching networks
- H04L43/16—Threshold monitoring
-
- 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
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S40/00—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them
Definitions
- the invention relates to the field of utility communication, and in particular to communication of real-time operational data between distant sites of an electric power utility enterprise. It departs from a communication method as described in the preamble of claim 1.
- Electric power utilities or transmission system operators own and operate electric power transmission networks interconnecting sites, such as power sources and substations, which despite being distant from each other some 100 km or more, have to be coordinated in one way or the other.
- sites such as power sources and substations
- a variety of messages are transferred over long distance communication links between distant sites of the utility in order to safely transmit and distribute electric energy.
- the transmission delay between transmitter and receiver is critical and should not exceed a few milliseconds up to some 10 ms.
- Dedicated remote tripping devices or protection signal transmission devices are generally used for transmitting protection or switching commands for distance and differential protection schemes in electrical high-voltage and medium- voltage networks and systems. Protection commands result, for example, in a circuit breaker being opened directly or indirectly and, in consequence in electrical disconnection of a selected part of the network or of the system. Conversely, other protection commands result in the opening of a circuit breaker in the remote station being prevented or blocked.
- a transmitter in a remote tripping device produces signals in accordance with the protection command, which are transmitted via a physical signal link.
- a receiver in another remote tripping device detects the transmitted signals and determines the corresponding number and nature of the protection commands.
- the physical signal link may involve radio waves or fiber optics, but preferably, the protection signals are transmitted over pilot wires, analog leased lines, voice channels of analog or digital communication systems, or even high-voltage electricity transmission lines, the latter being known as power line communication (PLC).
- PLC power line communication
- US 2003/081634 Al is concerned with conventional audio tone teleprotection via a dedicated audio telecommunication link between two substations, and including time division multiplexed frames being transmitted continuously from a sender to a receiver in a deterministic manner.
- a special framing pattern pre-selected pattern of 8 bits
- the known framing pattern is not detected repeatedly at the receiver override information signals are inserted into the de-framed data stream to prevent a noise signal from producing a false output state.
- the utility may rely on public or proprietary communication networks with non-deterministic behaviour.
- a Wide-Area communication Network designates a packet switched communication network interconnecting two sites of the utility, and comprising a number of IP networks with specific network elements such as routers, switches, repeaters and possibly optical transmission media at the physical layer.
- WANs are in general very reliable, however said network elements may cause irregular network delays, occasional bit errors and inherent link failures, which all contribute to a non-deterministic behaviour of the network.
- packet switched networks with individual data packets carrying destination addresses heavy load on a communication channel or a specific network element may lead to increased delay or packet loss, whereas link failure can cause delays due to reconfiguration of the routers.
- WANs can also be target of unlikely, but potentially harmful acts of intrusion comprising e.g. inserting intentionally wrong commands at one of the routers.
- any communication channel involving a WAN may be considered both non-deterministic, or non-synchronous, and non-secure.
- Use of non-deterministic communications for command and control means that one can not guarantee delivery nor the actual communication path taken by a packet.
- the use of the Internet increases the risk of critical control system communications failure, as attacks against other entities could greatly impact any control communications that uses this path or shares resources that touch the Internet.
- dedicated teleprotection systems monitor the state and delay of a communication system by means of dedicated loop test messages that operate as follows: two stations, A and B, are connected via a communication link. Station A transmits a special message to station B, which receives it and immediately sends back an "echo" to station A. When station A receives this "echo", it knows that the communication link is working, and it can also measure the transmission delay (half the time it takes the loop test message to travel from A to B and back to A). A loop test messages is typically sent once every few hours, accordingly, changes of the transmission delay in real-time can not be detected.
- Precision Time Protocol PTP Precision Time Protocol
- Standard two-way time synchronisation protocols such as IEEE 1588 define methods for synchronising devices via a communication network such as a Local Area Network (LAN), to a high precision (better than one microsecond).
- LAN Local Area Network
- VoIP Voice over IP
- IP Internet Protocol
- QoS Quality of Service
- RTP Real-Time Protocol
- IP Internet Protocol
- UDP User Datagram Protocol
- the former ensures that all the packets arrive at the receiver, but requires more bandwidth due to protocol overhead and it introduces more delay.
- the reliable transport protocols normally measure the round-trip delay in order to derive there from when messages should be repeated.
- unreliable protocols are lightweight and faster although the data stream may be subject to packet loss.
- a method for monitoring a packet-switched network via which real time VoIP data is transmitted is provided.
- Data packets containing real-time data are sniffed in order to monitor a QoS parameter.
- the QoS parameter comprises one of egress delay, ingress delay, jitter, roundtrip delay, packet loss, throughput, instantaneous signal loss, and accumulated content loss.
- a QoS Monitor blocks routing over the IP network and routes calls over an alternative network, such as a Switched Circuit Network (SCN).
- SCN Switched Circuit Network
- a non-deterministic communication channel comprising a Wide Area Network (WAN) with packet switched communication, such as e.g. an Internet Protocol (IP) network, is being monitored based on regular network traffic, i.e. by evaluating continually sent data packets carrying real-time operational data as a payload.
- IP Internet Protocol
- a permanent determination and monitoring of a channel quality is based on an evaluation, at a receiving node, of data packets continually transmitted by a sending node. These continually or repeatedly transmitted data packets may comprise, as operational data, identical payloads reflecting current states rather than state changes. Ultimately, the reliability of a communication over a non-deterministic channel without message confirmation is increased.
- the communication method is most beneficially used in an electric power system, where the data packets comprise protection commands to protect a power line between two sites of the electric power system, and where a site is a power source, a power sink, or a substation.
- the protection of the power line may be a distance or differential protection scheme, and result e.g. in a blocking, unblocking, or permissive state of a switching device at the remote site.
- the repeatedly transmitted data packets may be seen as replacing a conventional guard signal in conventional teleprotection channels.
- the receiving node determines channel availability as a binary and rapidly updatable channel quality measure.
- the receiving node verifies whether data packets with the expected type of payload are actually received, and whether the delay in-between successively received data packets is in the expected range. If the time elapsed between successive data packets exceeds a certain threshold, the channel availability is, at least temporarily, considered insufficient. Appropriate measures are then taken at the receiving node, such as alarm generation, conversion to a stand-alone or island operation mode, or, in case a signal is deemed missing, a switching device at the second site being unblocked.
- the proposed protocol for payload transmission and channel supervision comprises including, in the data packets, a send sequence number.
- Send sequence numbers are preferred over time stamps because of possible irregularities in the time source at the sender due to e.g. clock synchronisation, manual time setting or daylight savings time.
- sequence numbers can be detected and logged, such as packet loss, packet duplication and reception of packets in the wrong order, i.e. not in the order in which they had been dispatched. All these errors point to a degrading channel quality in the WAN.
- the data packet comprises a response request flag. If the latter is set, a response message is prepared by a destination node of the original data packet and immediately returned to the source or originating node.
- the response message comprises the received "send sequence number".
- the source node can estimate a round trip delay or time of the communication channel. If this permanent response time measurement then detects a delay that exceeds a configurable threshold, an alarm is generated informing the user that the quality of the non-deterministic communication channel is no longer guaranteed, and that a different communication channel should be chosen, or that the message contents should be temporarily ignored.
- the sending node is connected to a relay at the first site or substation, and permanently transmitting a state received from the latter.
- cyber security aspects of the proposed transmission over non-secure communication channels is taken care of by a hash or message digest that is transmitted as part of the data packet and calculated on the basis of the header and payload fields.
- the hash enables to verify the authenticity of the data packet, and thus provides, if needed in combination with the sequence number and node address, for a basic protection against various security threats.
- the proposed protocol is implemented in a peer-to-peer fashion in both communication nodes, such that each node can independently measure the channel quality and signal alarms.
- Fig.1 schematically depicts a utility communication network
- Fig.2 is an excerpt of an exemplary data packet
- Fig.3 schematically shows a sequence of maintenance packets and one response packet.
- Fig.l depicts a utility communication network with a first node or terminal 11, a second node or terminal 21, and a Wide Area Network (WAN) 30 as part of a non-deterministic communication channel, e . g . b as ed on User Datagram Protocol (UDP) with unacknowledged transmission between the two nodes.
- the two nodes 11, 21 are dedicated teleprotection devices located at a first substation 10 and at a second substation 20, respectively, and hardwired to a number of protection relays 12, 22 or other secondary equipment of the respective substation.
- the two nodes 11, 21 may be interconnected via other communication channels, such as a Power Line Communication (PLC) channel along an overhead power line 40 between the two substations 10, 20.
- PLC Power Line Communication
- the relays 12, 22 in turn are connected to the primary equipment of the substation and provide a signal or state to be transmitted, e.g. a tripping signal or command related to a distance protection function of the overhead power line 40.
- Fig.2 shows an excerpt of an exemplary data packet 50 to be sent, by the first node 11, across the non-deterministic communication channel 30 to the second node 21.
- the data packet comprises a header, payload and trailer as part of a teleprotection application layer.
- the header includes, among other fields, special header fields with a Response-Request flag 51, a teleprotection Node Address 52, and a send sequence number 53.
- the payload field 54 comprises one or several signals or protection commands in the form of a relatively short bit sequence. It is followed by a first trailer field with a message digest or hash 55 calculated on the basis of the header and payload fields.
- the hash provides for a basic protection against, and enables, if needed in combination with the sequence number 53 and node address 52, detection of various security threats, e.g. unauthorized (faked) messages, wrong partner, man-in-the-middle, or message replay. Further trailer fields may follow, such as a retransmission count 56 that is incremented in case of a retransmission, at an increased repetition rate and following a particular event, of otherwise unchanged data packets with identical sequence number and hash.
- the application layer data is embedded in headers and trailers according to the OSI transport (UDP) network (IP) and physical (Ethernet) layers (not shown in Fig.2).
- Fig.3 shows an exemplary sequence of messages 50, 50', 50" exchanged between nodes
- the first node 11 continually sends data packets at regular intervals separated by idle periods with no sending activity, e.g. every 5 ms.
- the data packets are received by the second node 21, and as long as the messages are received in order, and/or with the expected inter-message delays ⁇ t, the channel 30 is assumed to be available, and the payload conveyed by the messages is duly evaluated at the receiving end.
- the response request flag 54 in the data packet 50" is set, upon which the second node responds with a response message 60.
- the response requests are sent periodically, but at a much lower rate (e.g. every 100 ms to 10 sec) than the data packets without response request.
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Environmental & Geological Engineering (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
- Small-Scale Networks (AREA)
Abstract
Description
Claims
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
RU2011134034/07A RU2511219C2 (en) | 2009-01-15 | 2010-01-12 | Data transmission method and system |
ES10700535.7T ES2529549T3 (en) | 2009-01-15 | 2010-01-12 | Communications method and system |
EP10700535.7A EP2387829B1 (en) | 2009-01-15 | 2010-01-12 | Communication method and system |
CN201080004954.XA CN102282776B (en) | 2009-01-15 | 2010-01-12 | Communication means and system |
CA2748483A CA2748483C (en) | 2009-01-15 | 2010-01-12 | Communication method and system |
BRPI1007338A BRPI1007338A2 (en) | 2009-01-15 | 2010-01-12 | communication method and system |
US13/181,709 US9001675B2 (en) | 2009-01-15 | 2011-07-13 | Communication method and system |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP09150630A EP2211479A1 (en) | 2009-01-15 | 2009-01-15 | Communication method and system |
EP09150630.3 | 2009-01-15 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/181,709 Continuation US9001675B2 (en) | 2009-01-15 | 2011-07-13 | Communication method and system |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2010081798A1 true WO2010081798A1 (en) | 2010-07-22 |
Family
ID=40791232
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2010/050273 WO2010081798A1 (en) | 2009-01-15 | 2010-01-12 | Communication method and system |
Country Status (8)
Country | Link |
---|---|
US (1) | US9001675B2 (en) |
EP (2) | EP2211479A1 (en) |
CN (1) | CN102282776B (en) |
BR (1) | BRPI1007338A2 (en) |
CA (1) | CA2748483C (en) |
ES (1) | ES2529549T3 (en) |
RU (1) | RU2511219C2 (en) |
WO (1) | WO2010081798A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2432133A1 (en) | 2010-09-19 | 2012-03-21 | ABB Technology AG | Utility communication method and system |
CN103997123A (en) * | 2014-05-07 | 2014-08-20 | 国家电网公司 | Intelligent-transformer-substation circuit breaker remote control system and method based on sniffing of idle state |
CN104659765A (en) * | 2015-02-15 | 2015-05-27 | 国家电网公司 | Channel configuration and protection scheme applied to multi-terminal radiation network of power system |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2614598B1 (en) * | 2010-09-08 | 2016-04-13 | General Electric Technology GmbH | Method for tele-protection of power line network |
EP2557646B1 (en) * | 2011-08-10 | 2020-07-01 | ABB Power Grids Switzerland AG | Configuration of an IEC 61850 teleprotection IED for inter-substation communication |
EP2608417B1 (en) * | 2011-12-23 | 2020-07-22 | Power Plus Communications AG | Method and system for monitoring the condition of a supply grid |
FR2992791B1 (en) * | 2012-06-29 | 2016-03-11 | Alstom Technology Ltd | METHOD OF OPTIMIZING THE OPERATION OF A TELEPROTECTION SYSTEM |
ES2572956T3 (en) * | 2012-07-31 | 2016-06-03 | Abb Research Ltd. | Synchronization of clocks for differential line protection |
CN102970180B (en) * | 2012-11-01 | 2015-03-04 | 武汉大学 | Real-time simulation method of communication delay of wide area measurement system of electric power system |
WO2014108173A1 (en) | 2013-01-08 | 2014-07-17 | Telefonaktiebolaget L M Ericsson (Publ) | Distributed traffic inspection in a telecommunications network |
US20150236904A1 (en) * | 2014-06-02 | 2015-08-20 | Hsiaokuei Tsui | Internet Device Architecture to Save Power And Cost |
EP3082207A1 (en) | 2015-04-14 | 2016-10-19 | ABB Technology AG | Method for transmitting a teleprotection command using sequence number |
EP3174248A1 (en) * | 2015-11-26 | 2017-05-31 | R3 - Reliable Realtime Radio Communications GmbH | Communication system |
EP3540910B1 (en) * | 2018-03-13 | 2021-05-05 | ABB Schweiz AG | Enabling communication between communication devices of substations |
US11336683B2 (en) | 2019-10-16 | 2022-05-17 | Citrix Systems, Inc. | Systems and methods for preventing replay attacks |
CN116508295A (en) * | 2020-11-30 | 2023-07-28 | 华为技术有限公司 | In-band edge-to-edge round trip time measurement |
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2009
- 2009-01-15 EP EP09150630A patent/EP2211479A1/en not_active Withdrawn
-
2010
- 2010-01-12 CN CN201080004954.XA patent/CN102282776B/en active Active
- 2010-01-12 WO PCT/EP2010/050273 patent/WO2010081798A1/en active Application Filing
- 2010-01-12 EP EP10700535.7A patent/EP2387829B1/en active Active
- 2010-01-12 BR BRPI1007338A patent/BRPI1007338A2/en not_active IP Right Cessation
- 2010-01-12 RU RU2011134034/07A patent/RU2511219C2/en not_active IP Right Cessation
- 2010-01-12 CA CA2748483A patent/CA2748483C/en not_active Expired - Fee Related
- 2010-01-12 ES ES10700535.7T patent/ES2529549T3/en active Active
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2011
- 2011-07-13 US US13/181,709 patent/US9001675B2/en active Active
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WO1994003002A1 (en) * | 1992-07-24 | 1994-02-03 | Comsource Systems Corporation | Frequency hopping time-diversity communications systems and transceivers for local area networks |
US20020105909A1 (en) | 2001-02-07 | 2002-08-08 | Mark Flanagan | Quality-of-service monitor |
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EP2432133A1 (en) | 2010-09-19 | 2012-03-21 | ABB Technology AG | Utility communication method and system |
WO2012035093A1 (en) | 2010-09-19 | 2012-03-22 | Abb Technology Ag | Utility communication method and system |
CN103119852A (en) * | 2010-09-19 | 2013-05-22 | Abb技术有限公司 | Utility communication method and system |
US9571157B2 (en) | 2010-09-19 | 2017-02-14 | Abb Schweiz Ag | Utility communication method and system |
CN103997123A (en) * | 2014-05-07 | 2014-08-20 | 国家电网公司 | Intelligent-transformer-substation circuit breaker remote control system and method based on sniffing of idle state |
CN103997123B (en) * | 2014-05-07 | 2016-03-30 | 国家电网公司 | A kind of based on smelling the circuit breaker of intelligent transformer substation remote control system and method for visiting idle condition |
CN104659765A (en) * | 2015-02-15 | 2015-05-27 | 国家电网公司 | Channel configuration and protection scheme applied to multi-terminal radiation network of power system |
Also Published As
Publication number | Publication date |
---|---|
RU2011134034A (en) | 2013-02-20 |
CA2748483C (en) | 2016-05-03 |
US20110286350A1 (en) | 2011-11-24 |
RU2511219C2 (en) | 2014-04-10 |
BRPI1007338A2 (en) | 2016-08-09 |
EP2387829B1 (en) | 2015-01-07 |
ES2529549T3 (en) | 2015-02-23 |
EP2387829A1 (en) | 2011-11-23 |
CA2748483A1 (en) | 2010-07-22 |
EP2211479A1 (en) | 2010-07-28 |
US9001675B2 (en) | 2015-04-07 |
CN102282776B (en) | 2016-05-11 |
CN102282776A (en) | 2011-12-14 |
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