CN104219014A

CN104219014A - PTP clock synchronization method based on SDH transmission network

Info

Publication number: CN104219014A
Application number: CN201310216794.0A
Authority: CN
Inventors: 方愉冬; 杨贵; 裘愉涛; 盛海华; 方天宇; 张志峥; 王悦
Original assignee: NR Electric Co Ltd; Zhejiang Electric Power Co
Current assignee: State Grid Zhejiang Electric Power Co Ltd; NR Electric Co Ltd; Zhejiang Electric Power Co
Priority date: 2013-06-03
Filing date: 2013-06-03
Publication date: 2014-12-17

Abstract

The invention discloses a PTP clock synchronization method based on an SDH transmission network. The clock device of one substation is selected from various substations requiring synchronization as a PTP main clock device, and the clock devices of other substations serve as PTP slave clock devices, the main clock device and the slave clock devices are connected through E1 channels provided by SDH/MSTP equipment, the SDH/MSTP equipment of the SDH transmission network is connected to the main clock device and slave clock devices of the substations through E1 interfaces, the clock frequencies of the main clock device and slave clock devices of the substations are used for extracting clock frequency of the SDH equipment from E1 terminal signals of the SDH/MSTP equipment through a built-in a phase lock loop. By the aid of the method, the reliability of network synchronization of the substations can be improved.

Description

A kind of clock synchronization compliant with precision time protocol synchronous method based on SDH transmission network

Technical field

The present invention relates to the formations such as the SDH transmission network of electric power system, PTP master-salve clock based on the clock synchronization compliant with precision time protocol synchronizing network of SDH transmission network, be specifically related to a kind of method of PTP master-salve clock synchronization.

Background technology

SDH/MSTP transmission network is the basis forming electrical power system transmission net, transmission network is primarily of SDH(Synchronous Digital Hierarchy, SDH (Synchronous Digital Hierarchy)) equipment or MSTP equipment forms, SDH/MSTP equipment provides the various interface such as E1, Ethernet, realizes the access of the various signal such as E1, Ethernet.

In order to effectively realize the clock synchronous of different SDH/MSTP equipment room, meeting the synchronisation requirement between electric power system station, realizing the defencive function between transformer station.At present, when each transformer station of electric power system all adopts GPS or the Big Dipper pair, mode realizes clock synchronous, IRIG-B code, PTP(Precision Time Protocol is adopted in transformer station, split-second precision agreement) mode realizes the synchronous of full station equipment, as shown in Figure 1, because mode when GPS or the Big Dipper pair is affected by the external environment very large, when weather when between transformer station is inconsistent, the time between transformer station all can be caused as rainy, cloudy etc. to there is very large deviation (ms level or larger), the synchronization accuracy requirement between transformer station cannot be met.In addition; step-out when cloudy day or the weather such as to rain can cause GPS or the Big Dipper pair; clock after step-out in transformer station is by punctual for maintenance state; namely keep synchronous with the master clock in transformer station; master clock when step-out with the crystal oscillator of self for station entirely provides clock reference; frequency departure is there is between the crystal oscillator due to each master clock; to cause in this case realizing synchronously between each transformer station; this cannot normally work causing the protection relying on clock synchronous between transformer station, will cause malfunction time serious.Above situation will badly influence the reliability of power system operation, and this brings great potential safety hazard by giving the reliability service of whole electric power system.

Based on above analysis, the present inventor carries out Improvement to the clock synchronization mode of SDH transmission network, and this case produces thus.

Summary of the invention

Object of the present invention, be to provide a kind of clock synchronization compliant with precision time protocol synchronous method based on SDH transmission network, it can improve the reliability of Network Synchronization between transformer station.

In order to reach above-mentioned purpose, solution of the present invention is:

A kind of clock synchronization compliant with precision time protocol synchronous method based on SDH transmission network, in each transformer station synchronous when needed, clockwork in one of them transformer station selected is as PTP clock equipment, clockwork in other transformer station is all set as that PTP is from clockwork, main, be connected from the E1 passage provided by SDH/MSTP equipment between clockwork, SDH/MSTP equipment on SDH transmission network is by the master in e1 port access transformer station, from clockwork, master in transformer station, from the e1 port signal of SDH/MSTP equipment, extracted the clock frequency of SDH equipment by built-in phase-locked loop from the clock frequency of clockwork.

The mode of above-mentioned master and slave clockwork transmission PTP message is: master and slave clockwork carries out clock synchronous by E1 channel transfer PTP message, the E1 transceiver channel of master and slave clockwork distributes identical channel path in SDH transmission network, and the transmitting-receiving of alternate channel adopts other E1 channel path that transceiver path is identical to transmit.

After adopting such scheme; the present invention realizes the clock synchronous between transformer station by SDH/MSTP transmission network transmission PTP information; precision during in order to promote pair and reliability; the clock rate synchronization mode of the master and slave clockwork in transformer station and SDH/MSTP transmission network is adopted to realize Frequency Synchronization; by the clock equipment of in transformer station be in other transformer stations from clockwork pair time; realize the clock synchronous between transformer station, solve clock between transformer station poor respectively by GPS synchronization accuracy, the problem protecting demand between station cannot be met.

Accompanying drawing explanation

Fig. 1 is existing transformer station setting network schematic diagram;

Fig. 2 is transformer station's setting network schematic diagram in the present invention.

Embodiment

Below with reference to accompanying drawing, technical scheme of the present invention is described in detail.

As shown in Figure 2, the invention provides a kind of clock synchronization compliant with precision time protocol synchronous method based on SDH transmission network, in N number of transformer station synchronous when needed (N is natural number), set clockwork in one of them transformer station as PTP clock equipment, specifically using which as PTP clock equipment, can determine according to actual demands of engineering, that clockwork in selected transformer station 1 is as clock equipment in the present embodiment, and the clockwork in other transformer station is all set as that PTP is from clockwork, to guarantee that each transformer station has unified clock source.

Master clock in each transformer station, the E1 passage provided by SDH/MSTP equipment from clockwork is connected, this E1 passage and SDH/MSTP equipment stringent synchronization, its clock frequency adopts SDH/MSTP device transmission side clock frequency to extract and obtains, SDH/MSTP equipment on SDH transmission network is by the master clock in e1 port access transformer station, from clockwork, master in transformer station, from the e1 port signal of SDH/MSTP equipment, extracted the clock frequency of SDH equipment by built-in phase-locked loop from the clock frequency of clockwork, guarantee the master in transformer station, synchronous with SDH/MSTP device frequency from the clock frequency of clockwork.

Master clock, carry out clock synchronous from clockwork by E1 channel transfer PTP message, the E1 transceiver channel of master and slave clockwork distributes identical channel path in SDH transmission network, the transmitting-receiving of alternate channel adopts other E1 channel path that transceiver path is identical to transmit, ensure that the transmitting-receiving transmission delay of PTP signal in SDH transmission network is consistent with this, when there is passage bridge, the transmitting-receiving transmission delay of PTP signal in SDH transmission network is still consistent, effectively prevent PTP Time delay measurement generation asymmetric error, precision during guarantee PTP couple.

Adopt this clock synchronizing method, can effectively solve each transformer station by GPS or the Big Dipper between station constantly to time error.Specific implementation step is as follows:

(1) master clock definition: the clockwork only defined in each transformer station synchronous when needed in a transformer station is PTP clock equipment, clockwork in other transformer station is PTP from clockwork, guarantees that each transformer station has unified clock source;

(2) by distributing: during all to be undertaken pair by independently E1 passage and master clock from clock in each transformer station, this E1 passage need ensure receive-after-transmit time delay consistent, the path of carrying out asymmetry compensation as needed when can not ensure that receive-after-transmit time delay is consistent or select other receive-after-transmit time delay consistent in PTP function, E1 passage for subsequent use requires that receive-after-transmit time delay is consistent equally.PTP clock equipment needs to provide each substation PT P of multiple E1 Interface realization from the access of clockwork;

(3) Frequency Synchronization: the e1 port arranging the master and slave clockwork of PTP is operated in from clock module, the e1 port arranging SDH/MSTP equipment is operated in net synchronous mode, the clock frequency of the master and slave clockwork of PTP extracts the clock frequency of SDH equipment from the e1 port signal of SDH/MSTP equipment by the built-in phase-locked loop of equipment, guarantee that the master and slave clock frequency of PTP is synchronous with SDH/MSTP device frequency;

(4) during master clock pair: when PTP clock equipment to be undertaken pair by GPS or the Big Dipper, and with this time for when fiducial time, the PTP that is power transformation station equipment and other transformer station to carry out pair from clock;

(5) stand in pair time: the clockwork in each transformer station by mode during PTP or IRIG-B couple be in station by pair time equipment to carry out pair time, guarantee that station equipment has identical time value;

(6) stand between pair time: when the PTP clock equipment between transformer station and PTP carry out the measurement of PTP communication channel delay and master-salve clock pair from clockwork by the mechanism specified IEC61850-2009 standard, guarantee that the master and slave clock time of PTP is consistent.

Above embodiment is only and technological thought of the present invention is described, can not limit protection scope of the present invention with this, and every technological thought proposed according to the present invention, any change that technical scheme basis is done, all falls within scope.

Claims

1. the clock synchronization compliant with precision time protocol synchronous method based on SDH transmission network, it is characterized in that: in each transformer station synchronous when needed, clockwork in one of them transformer station selected is as PTP clock equipment, clockwork in other transformer station is all set as that PTP is from clockwork, main, be connected from the E1 passage provided by SDH/MSTP equipment between clockwork, SDH/MSTP equipment on SDH transmission network is by the master in e1 port access transformer station, from clockwork, master in transformer station, from the e1 port signal of SDH/MSTP equipment, extracted the clock frequency of SDH equipment by built-in phase-locked loop from the clock frequency of clockwork.

2. a kind of clock synchronization compliant with precision time protocol synchronous method based on SDH transmission network as claimed in claim 1, it is characterized in that: the mode of described master and slave clockwork transmission PTP message is: master and slave clockwork carries out clock synchronous by E1 channel transfer PTP message, the E1 transceiver channel of master and slave clockwork distributes identical channel path in SDH transmission network, and the transmitting-receiving of alternate channel adopts other E1 channel path that transceiver path is identical to transmit.