Transmission & distribution
Strong entry in the relay race1 January 2009
ABB’s REF 615 dedicated feeder protection relay has been designed specifically for the protection, measurement and supervision of utility substations and industrial power systems. It provides IEC 61850-based connectivity and interoperability
This new relay has been engineered to exploit the full potential of the IEC 61850 standard for communication and interoperability of substation automation devices. It provides main protection for overhead lines, cable feeders and busbar systems of distribution substations. It can be installed in any kind of distribution network, regardless of the applied power system earthing principle.
It offers short-circuit, time overcurrent and thermal overload protection, as well as directional and non-directional earth-fault protection, sensitive earth-fault protection (SEF) and transient-measuring earth fault protection including detection of intermittent earth-faults in cable networks.
To provide for automatic extinguishing of arc faults on open wire overhead lines, the relay incorporates a flexible three phase multi-shot auto-reclose function. When enhanced with an optional plug-in card, it also offers a three-channel arc-fault protection system for supervision of the switchgear circuit breaker, cable and busbar compartment. REF 615 also integrates basic control functionality, which facilitates the control of one circuit breaker via the relay’s HMI or remote control system. To protect the relay from unauthorised access and to maintain the integrity of information, the relay has been provided with a four-level, role-based user authentication system, with individual passwords for the viewer, operator, engineer and administrator level.
REF 615 supports the new IEC 61850 standard for inter-device communication in substations. It also supports the industry standard Modbus protocol. The implementation of IEC 61850 covers both vertical and horizontal communication, including GOOSE (Generic Object Oriented Substation Event) messaging and parameter setting (in accordance with IEC 61850- 8-1) that allows the transmission of data to peer devices in the substation. The substation configuration language (SCL) enables the use of engineering tools for automated configuration, commissioning and maintenance of substation devices.
Pre-emptive condition monitoring
To ensure optimised system availability, the relay features a comprehensive choice of monitoring functions to supervise the relay itself, the circuit breaker trip circuit and the circuit breaker. Depending on the chosen device configuration, the relay monitors the wear and tear of the circuit breaker, the spring charging time of the circuit breaker operating mechanism and the gas pressure of the breaker chambers. It also supervises the breaker travel time and the number of circuit breaker operations to provide basic information for scheduling circuit breaker maintenance.
Since the relay is designed specially for feeder protection, it can be rapidly set up and commissioned, once it has been given the application specific relay settings. It also offers flexibility – it can be adapted to meet the particular requirements of an individual application.
Connectivity packages that contain complete descriptions of ABB’s protection relays, with data signals, parameters and addresses, enable the relay to be configured automatically via MicroSCADA Pro system or the PCM 600 relay setting and configuration tool.
The plug-in type relay design speeds up installation and testing of the protection. The factory-tested relay units can be withdrawn from the relay cases during switchgear factory and commissioning tests. The plug-in design also speeds up maintenance work because relay units can be easily exchanged. The relay case provides automatic short circuiting of the CT (current transformer) secondary circuits to prevent hazardous voltages from arising in the CT circuits when a relay plug-in unit is withdrawn from its case. The pull-out handle locking the relay unit into its case can be sealed to prevent the unit from being unintentionally withdrawn from the relay case.