syntheticplatformdetailintroduction.ppt

Synthetic platform detail introductionContentsWhy to build up synthetic platformSwitchgear making&breaking testing techniquesEnergy Sh-Lab synthetic platform structureWhy to build up synthetic platformBuild up a single phaseprototype based on theprevious experienceSubject it to short circuittest to confirm the initialassumptionIntroduce modificationsbased on test results&repeat testthe requiredperformance of FPTCobtained?Build up 3 phase prototypethe requiredperformance of FPTCobtained?YesNoYesNoStandard development processProcess needs&limits from conventional test plant Single phase testing accounts for 70%of the total development testingConventional test plant generator or network-Large,cumbersome to operate-Expensive-Difficult to make analysis if test failedThree phase short power needs for direct testingAbove table shows the three phase short circuit power that is required from the primary source(generator or public network)to perform direct tests on MV CB for the IEC rated values.The approximate cost of a 2000MVA station powered by short circuit generator is 200 million RMB.8 8101012.512.516162020252531.531.5404036500620780100012501600200025002433042052067083010001300170017.5250305380490605760950120012170210260330420520660850Voltage(kV)Voltage(kV)Current(kA)Current(kA)Three phase short power(MVA)for direct testingThree phase short power(MVA)for direct testingPrinciple of synthetic test Divide short-circuit breaking into 2 phases to reduce necessary power High current phase(short-circuit)High voltage phase(Transient recovery voltage)High current phase:supply the short circuit test current from a source of much lower voltage than the breaker rated voltage High voltage phase:provide voltage stress after interruption from a low power high voltage sorce Synthetic lab is thus composed of 2 banks A high current one A high voltage one with good time coordination between both 1 msSeparation sufficient to withstand TRVsopening of contactstExtinction of arcAdvantage of synthetic testingEffectiveness:Widely accepted as an equivalent method as direct testing.Efficiency:Producing large number of tests quickly.Economic:Significant cost reduction on the installation compare with the cost of power source needed for direct testing.Easy to operate and maintain.Protection of prototype under test:Significantly reduction of damage to the prototype even if the test failed.Convenience for analysis Provide possibility to stop testing when time analysis of results or prototype modification is needed.Suitable environment to attempt the sophisticated measurements required to know what is happening in the interrupter,particularly during the few vital microseconds immediately before and after current zero.Switchgear making&breaking testing techniques3 basic types of short circuit test for MV&HV CBShort circuit current making&breaking testLoad current making&breaking testShort time withstand&peak withstand current testThe most demanding test for CB is the breaking of its rated short circuit current.Most of the test station are fed by specially designed short circuit generator,while others are connected directly to the public network.Certification tests on MV SWGR are always carried out by direct tests,i.e.the short circuit current supplied from a source with an open circuit voltage equal to the rated voltage of the CB.Certification test on HV SWGR are normally carried out by synthetic tests due to the capacity limits of the source.IEC short circuit test requirements Test duty 1,2,3&4 involve breaks with symmetrical currents Test duty 5 is known as“break with asymmetrical currents”and the severity of the test strongly depends on the instant of contact separation.The standard requires that timing is adjusted so that the FPTC separates its contacts in a major loop of current.Test dutyTest dutySequenceSequenceTest currentTest current(%of rated value)(%of rated value)%of DC%of DCcomponents(*)components(*)No.1O-0.3-CO-3-CO orO-3-CO-3-CO10%20%No.2O-0.3-CO-3-CO orO-3-CO-3-CO30%20%No.3O-0.3-CO-3-CO orO-3-CO-3-CO60%20%No.4O-0.3-CO-3-CO orO-3-CO-3-CO100%20%No.5O-0.3-CO-3-CO orO-3-CO-3-CO100%Depends on thebreakers min.operating timeRemark(*):The%of DC component is referred to the ponent for a time constant of 45ms(X/R=14)Load current making&breaking tests Load currents making&breaking tests do not normally impose a demanding duty on the switchgear as fault currents do.However,switch failure like reignitions or current chopping can cause severe over-voltage and damage the load insulation.Testing is required in particular for the disconnection to capacitive loads(like power factor correction capacitor&unloaded cables)&inductive loads(like induction motors&unloaded transformers)for two main reason:To satisfy customer,who is mainly concerned with maximum overvoltage likely to be generated by the SWGR in service and its relation to the insulation level of the network where it is going to be installed.To allow designer to find a compromise between t