Sepam - HV/MV Protection and control units (ENG) - Trinet

Synchro-checkANSI code 25function n° F171 synchro-check on first voltageacquisition boardF181 synchro-check on secondvoltage acquisition boardOperationThe synchro-check function is single-phase.It is designed to allow a circuit breaker to closewithout the risk of dangerous coupling of two voltagesUsync 1 and Usync 2.The voltages that are compared may be 2 phase-tophasevoltages Uxy or two phase-to-neutral voltages Vx.The relay picks up if the voltages compared areequal, i.e., if the phase, frequency and amplitudedifferences are within the set limits.In addition, it comprises 4 operating modes which allow coupling in different casesof voltage absence:c mode 1 if voltage Usync 2 is present and voltage Usync1 is absent,c mode 2 if voltage Usync 1 is present and voltage Usync 2 is absent,c mode 3 if one of the two voltages is present and the other one is absent,c mode 4 if one of the two voltages or both voltages are absent.The presence of each of the 2 voltages is detected by comparing the voltage withthe high setting (Us high).The absence of each of the 2 voltages is detected by comparison with the lowsetting (Us low).Anticipation*It is possible to anticipate function action by a time Ta taking into account thefrequency difference and circuit breaker closing time in order for synchronism to bereached at the time of coupling.MeasurementsThe following measurements may be accessed via the pocket terminal:c phase difference between voltages Usync 1 and Usync 2,c amplitude of voltage Usync 1,c amplitude of voltage Usync 2.Block diagramUsync 1Usync 2∆ϕ + 360 ∆F Ta < dPhisF171/4F181/4U > Us high∆F < dFS&U > Us highF171/5U > UsF181/5high∆U < dUSF171/6F181/6F171/1F181/1mode 2≥1F171/3F181/3&&≥1U > Us high0mode 3mode 10.1sF171/2F181/2U < Us low&≥1mode 4U < Us lowF172/1**F182/1**F172/2**F182/2*** available as version 9802 SFT2800.** available as version 9940 SFT2800.2/58 Protection functions