1MRS 755539 Feeder Protection RelayOperator’s Manual - ANSI VersionREF 610394. Commissioning and maintenanceThe relay should be subject to regular tests and maintenance in accordance withnational regulations and instructions.Prior to commissioning, the functionality of the application-specific relayconfiguration and settings have to be tested.During relay commissioning, the operation of short-circuit and ground-faultprotection is to be tested using secondary injection testing to secure personal safety.Additionally, correct operation of input and output signals to and from the relayshould be verified.REF 610 is a numerical protection relay with functionality implemented in the relaysoftware configuration. Software functionality does not change over time and therelay performs extensive self-supervision during operation. Therefore, it is notnecessary to perform extensive relay testing during periodic maintenance.When the protection relay is operating under the specified conditions (refer to theTechnical Reference Manual), the manufacturer recommends preventivemaintenance to be performed every five years. This periodically performedpreventive maintenance is to be carried out to secure correct and safe operation ofthe relay. When performing preventive maintenance, the correct functionality of therelay is to be verified as well as the wiring circuitry to and from the relay.If the environmental conditions at the relay operating site differ from thosespecified, for instance temperature and humidity, or if the atmosphere around therelay contains chemically active gases or dust, the relay ought to be visuallyinspected. At the visual inspection, the following should be observed:• Signs of mechanical damage on the relay, contacts and relay case.• Rust spots or signs of corrosion on the terminals or case.4.1. Commissioning instructionsRelay commissioning is carried out to confirm correct operation of the relay whenit is taken into use. Polarity checking of phase current transformers (CTs) should beperformed to confirm that the wiring circuitry between the CTs and the relay iscorrect, which is a prerequisite for the protection functions in the relay to operatecorrectly. The circuit breaker tripping circuit, interlocking and signalling wiringshould also be tested.When commissioning the relay, secondary injection testing is performed to securepersonal safety in case of short circuits or ground faults in the system. If desired,secondary injection testing can also be used for more elaborate testing of the relay’sfunctionality.Danger!Do not open the secondary circuit of a current transformer duringany phase of the testing when the primary circuit is live. The highvoltage generated by an open CT secondary circuit may be lethaland damage instruments and insulation.!