Presentation on theme: "IEC conformance test and the required network bandwidth"— Presentation transcript:
1IEC 61850-9-2 conformance test and the required network bandwidth Smart Grid Testing departmentWoohyun Seo
2Contents Merging Unit Tripping in Process Bus Conformance test Introduction, Advantages, StandardsTripping in Process BusConformance testNetwork Bandwidth for Process BusConclusion
31. Merging Unit - Introduction BusbarAnalog Input TransformersAnalog MeasurementA/D conversionare moved away from the IEDs and “are placed” into the merging unitConventional CTs/VTsAdvantage. Good saturation curveDisadvantage. Signal level output. Noise influenceNon-Conventional CTs/VTsMerging UnitProprietary LinkControlled Ethernet PortsLine protectionPIOC, PTOV, …Bay controllerCSWI, CSYN, …Device control interfaceProcess BusTime synchConfiguration
41. Merging Unit - Advantages Advantage of process bus with MERGING UNITReduce wiring cables and # of CTs/VTsIn conventional scheme, every IED needs CT(s) and/or VT(s) for processingImproved measuring accuracyShort distance between CTs/VTs and signal processorAdopting high-performance eCT/eVTSmall, Light, Broad dynamic range, Isolation between primary & secondary circuits, etcUnified platform for information sharingMerging unit broadcast the digitized measured data based on IEC standard
51. Merging Unit - Standards Signal processing interfaceDigital interface(Communication)IEC TC38 WG37IEC TC57 WG10IEC , ADDITIONAL REQUIREMENTS FOR ELECTRONIC VOLTAGE TRANSFORMERSIEC , Specific Communication Service Mapping (SCSM) – Sampled values over serial unidirectional multidrop point to point linkIEC , ADDITIONAL REQUIREMENTS FOR ELECTRONIC CURRENT RANSFORMERSWithdrawnIEC , Specific communication service mapping (SCSM) – Sampled values over ISO/IECIEC , DIGITAL INTERFACE FOR INSTRUMENT TRANSFORMERSImplementation…Implementation Guideline for Digital Interface to Instrument Transformers using IECIEC , Stand Alone Merging UnitConformance test procedureTest procedures for Sampled Values Publishers according to the "Implementation Guideline for Digital Interface to Instrument Transformers using IEC " (9-2LE)Not published
72. Tripping in Process Bus GOOSE INGOOSE OUTSAMPLED VALUESTime requirement is more critical!!!
82. Tripping in Process Bus A/D signal processing time delayPrimary condition for available protectionGuideline : 3 ms (IEC )Packet jitter and latency controlPart of performance testOnly the total number of packets in 1 sec existedStandard based syntaxFollowing IEC and IEC seriesNetwork bandwidthLack of bandwidth makes packet lossOut of range from conformance test
93. Conformance test Conformance test procedure Documentation : 2 test casesConfiguration : 9 test casesCommunication services : 17 test cases50/60 Hz, 80/256 samplesAccording to “Guideline”, Time master is based on “PPS”
103. Conformance test SV conformance test Conformity Verify conformity and performancePerformance is very important for MUAccuracy test is not includedConformityConnecter and Link layer format verification100Base-FX full duplex with ST, MT-RJ, LC fibers or Rj45APDU or ASDU format verificationQuality and Test bit verification
113. Conformance test Performance test SV maximum delay criterion : ~3 ms(3.3 ms)Verification # of messages per cyclePPS pulseSV with SmpCnt=0SV delayPublisher(MU)Subscriber………PPS pulsePPS pulsemessages for 80 samples of 60 HzJitter and latency control are required!
123. Conformance test Limitation of SV conformance test Not verifying focusing on packet treatmentWhat if MU makes the signal processing delay?CT/VT or eCT/eVTVo, IoPPS pulseSV delaySignal processing delaySV with SmpCnt=0Vo, IoReal tripping time may be delayed
134. Network Bandwidth for Process Bus Background from IECTelegram length : 888bit(packet) + 96bit(interFrame)BW : 80samples*60Hz*984bits < 5Mbps (per stream)Reliable?
144. Network Bandwidth for Process Bus Simple testMerging Unit100Mbps, Max 2 streams, 80samples/HzTime Synch1 PPS from GPSSwitchSeparate network only for process bus with MUSwitching latency : 7 micro secondSwitching bandwidth : 9.2 GbpsTesting toolSmart bit applicationsPacket size : 140 bytes(SMV packet : 128 bytes)
154. Network Bandwidth for Process Bus 1 streamThroughputLatencyPacket LossPassed Rate(%)(01,01,01) to (01,01,02) (pks/sec)94.1273529Rate Tested(%)(01,01,01) to (01,01,02) (us)-CT70.0018.075.0018.680.0017.485.0017.790.0095.00100.00Rate Tested(%)(01,01,01) to (01,01,02) (%)70.000.00075.0080.0085.0090.0095.001.080100.005.789Network load : 5.88 MbpsSwitching bandwidth(9 Gbps) is enough to handle this amount of traffic load(9,000 / 5.88 = 1,530 ports can be supported)
164. Network Bandwidth for Process Bus 2 streamsThroughputLatencyPacket LossPassed Rate(%)(01,01,01) to (01,01,02) (pks/sec)88.4069061Rate Tested(%)(01,01,01) to (01,01,02) (us)-CT70.0018.975.0017.080.0019.085.0023.090.002649.695.00100.00Rate Tested(%)(01,01,01) to (01,01,02) (%)70.000.00075.0080.0085.0090.001.90695.007.156100.0011.577Network load : 11.6 Mbps= 2*5.8 MbpsNetwork load for 2 streams is similar to twice one for 1 stream
175. Conclusion Expectation Network Bandwidth measurement in the real (simulated) process bus networkTheoretically, 100 Mbps based network can handle more than 10 MUsBut, need to check if how many MUs can implementedFor more stable process bus implementation, the critical points will beActual A/D signal processing time delay in devicePacket jitter and latency delay from device