ABB RET615 Product Manual

Also see for RET615: Product guide Manual Manual Manual Manual

Contents

ABB RET615 Product Manual Manual pdf 16 page image

4. ApplicationRET615 provides main protection for two-windingpower transformers and power generator-transformer blocks. As of now, there are eightstandard configurations offering comprehensiveprotection functions for detection and eliminationof operational disturbance conditions and powertransformer faults.The standard configurations A, C, E and G areintended for power transformers with earthed HV-side neutrals. The A and E configuration featureslow impedance REF protection while the C and Gconfiguration offers high impedance REFprotection. The B, D, F and H configurations fittransformers with solidly-earthed LV-side neutralor the LV side with a neutral earthing resistor. TheB, D, F and H configurations also fit applicationsincluding a separate earthing transformer locatedwithin the area of protection. The A, B , E, and Fconfigurations also suit applications, where theturns ratio of the CT of the neutral earthing circuitdiffers from the turns ratio of the line CTs. The C,D, G and H configurations require that the turnsratios of the CTs are equal.Standard configurations E, F, G and H includephase-voltage protection and measurementfunctions which provide two-stage powertransformer overvoltage and undervoltageprotection and/or supervision.The optional RTD/mA module offered for thestandard configurations A-D allow up to eightanalog signals to be measured via the six RTDinputs and the two mA inputs using transducers.The RTD and mA inputs can be used formeasuring the oil temperature at the bottom andtop of the transformer. Furthermore, the RTD/mAinputs can be used for measuring the ambient airtemperature. The RTD inputs also offer thermalprotection of dry-type power transformers fittedwith Pt-100 temperature sensors. Temperaturemeasurement over the RTD/mA inputs extendsthe function of the three-phase thermal overloadprotection of the IED. Further, one of the RTDinputs can also be used as a direct resistancemeasuring input for position information of the on-load tap changer. Alternatively, the tap changerposition indication can be obtained via a mA-transducer. The analog temperature or tapchanger position values can, if required, be sentusing analog horizontal GOOSE messaging toother IEDs. Analog values can also, vice versa, bereceived from other IEDs over the station bus,thus improving the extent of relevant information.Transformer Protection and Control 1MRS756891 FRET615Product version: 4.016 ABB