ABB REX 521 Technical Reference Manual, Standard Configurations

Also see for REX 521: Operator's manual Technical Reference Manual, General Technical Reference Manual, General Operating guide Technical Reference Manual, Standard Configurations

Contents

ABB REX 521 Technical Reference Manual, Standard Configurations Manual pdf 202 page image

2021MRS751802-MUMProtection RelayTechnical Reference Manual, Standard ConfigurationsREX 521• In cases “Live-Dead”, “Dead-Live” and “Dead-Dead” no other conditions arechecked.• In the case “Live-Live” also the following must be fulfilled:• ∆U< dU setting• ∆f< df setting• ∆ϕ< dphi settingBefore the function block allows the CB closing, it ensures that the phase differencewill remain within the setting range until the CB closes.The command mode is used as a basic control principle of the synchro-checkfunction. In command mode, the synchro-check function directly uses the outputsignal to close the circuit breaker. The close command for example from the HMI isconnected to the synchro-check function. When the close command is activated, thesynchro-check function checks the closing criteria and if they are fulfilled, it willroute the command to the output relay of the protection relay. In this applicationexample the close signal is connected to the power output PO3.The command mode principle means that the interlocking logic related to the controlfunctionality will affect the synchro-check function as well. If blocking is needed itcan be carried out by using the ready-made interlocking logic, for example in a casewhere the phase-to-phase voltage is missing from either side of the circuit breakerbecause of the open miniature circuit breaker (MCB) of the measurement circuit.11.1.4. ConnectionsAll the necessary settings for the connections and signal routings can be set via theRelay Setting Tool or the local HMI.11.1.4.1. Protection signal routingThe settings for the protection signal routing can be implemented as described in thesecond application example (see Section 9.2. Incoming feeder, Basic B01). In thisapplication two different trip signals are used: Trip 1 for opening of the circuitbreaker of the incoming feeder and Trip 2 for opening of the circuit breaker of thetransformer feeder. In this application separate power output relays are used for Trip2 and CBFP (circuit breaker failure protection) function.11.1.4.2. Indication and control connectionsThe connections for indication and control can be implemented as described in firstapplication example (see Section 9.1. Outgoing feeder, Basic B01), except thesignals for the open and close buttons that in this example are disconnected. Localcontrol can be executed by HMI according to the instructions in REX 521 Operator’sManual (see Section 1.5. Related documents).11.1.5. ImplementationsIn the sections below a few implementation examples for the standard configurationH01 are presented.