ABB RET620 Product Manual

Also see for RET620: Manual

Contents

ABB RET620 Product Manual Manual pdf 9 page image

Table 1. Supported functions, continuedFunctionality CTs & VTsGeneric up-down counters, instance 7 ●Generic up-down counters, instance 8 ●Generic up-down counters, instance 9 ●Generic up-down counters, instance 10 ●Generic up-down counters, instance 11 ●Generic up-down counters, instance 12 ●Programmable buttons (16 buttons) ●Logging functionsDisturbance recorder ●Fault recorder ●Sequence event recorder ●Load profile ●● = Included,○ = Optional at the time of the order1) The function is to be used on high voltage winding side in the application2) The function is to be used on low voltage winding side in the application3) The function is to be used on high voltage winding side in the application,and uses calculated Io when HREF and varistor connection used4) The function is to be used on low voltage winding side in the applicationand,and uses calculated Io when HREF and varistor connection used5) Calculated Io is used for the residual current criteria3. Protections functionsThe IED features a three-phase, multi-slope stabilized (biased)stage transformer differential protection and an instantaneousstage to provide fast and selective protection for phase-to-phase short circuit, winding interturn fault and bushing flash-over protection. Besides the second harmonic restraint, anadvanced waveform-based blocking algorithm ensuresstability at transformer energization and the fifth harmonicrestraint function ensures good protection stability atmoderate overexcitation of power transformers. The restrictedearth-fault protection (REF) completes the overall differentialprotection providing detection of even single phase-to-earthfaults close to the neutral earthing point of the transformer.Either the conventional high-impedance scheme or thenumerical low-impedance scheme can be selected forprotection of the transformer windings. When the low-impedance REF protection is used, neither stabilizingresistors nor varistors are needed and, as a further benefit,the transforming ratio of the neutral earthing CTs can differfrom that of the phase current transformers. Due to its unitprotection character and absolute selectivity, REF does notneed to be time-graded with other protection schemes, andtherefore a high-speed fault clearance can be achieved.The IED also incorporates a thermal overload protectionfunction that supervises the thermal stress of the transformerwindings to prevent the premature aging of the insulation ofthe windings. Multiple stages of short circuit, phase-overcurrent, negative-phase-sequence and earth-fault backupprotection are separately available for both sides of the powertransformer. An earth-fault protection based on the measuredor calculated residual voltage is also available. The IED alsofeatures three-phase overvoltage protection, three-phaseundervoltage protection and residual overvoltage protection.Furthermore, the IED also offers circuit breaker failureprotection.Enhanced with optional hardware and software, the IED alsofeatures three light detection point-to-point lens sensors forarc fault protection of the circuit breaker, busbar and cablecompartment of metal-enclosed indoor switchgear.The arc fault protection sensor interface is available on theoptional communication module. Fast tripping increases staffsafety and security and limits material damage in an arc faultsituation. Optional high speed outputs help to minimize thearc impacts.Transformer Protection and Control 1MRS757846 ARET620Product version: 2.0ABB 9