Investigating the capabilities of SEL787 transformer protection relay using low level simulators

Protection relays play an integral part in electrical power systems. They monitor and detect abnormal system conditions and initiate the operation of protective devices like circuit breakers to take corrective action and restore the power system to its normal state. Over the years, the technology has evolved from the old electromechanical-based relays to the new microprocessor-based relays also known as intelligent electronic devices, such as the SEL 787 transformer protection relay. Correct operation of these devices is critical as malfunction or incorrect operation might lead to severe damage to protected equipment and costly power outages. In commissioning, maintenance and training fields, the correct operation and accuracy verification is determined through carrying out fault simulations on the relay using different types of test equipment or simulators. This thesis investigates the capabilities of SEL 787 relay by using low level fault simulators and setting the foundation for the development of a National Instrument CompactDaq and LabVIEW fault simulator. The thesis comprises the following three main parts: Part 1: SEL 787 Transformer protection relay In this thesis, research has been carried out on the design and application of the SEL 787 relay in transformer protection. The hardware components and the software platform used by the relay has been analysed. Investigation of the software tools to facilitate efficient simulations and hence explore the functionality of the relay has been conducted. Part 2: Fault simulators / Test equipment Focuses on the different types of fault simulators in particular low level simulators like the SEL RTS system. Simulations where carried out on the SEL 787 relay using the SEL RTS system. The simulation results were analysed using standards and manufacturer specifications. Part 3: LabVIEW CompactDaq Simulator Involves the proposed design of a low level simulator using the CompactDaq modules and LabVIEW software. Analysis of the CompactDaq modules was conducted. Tests were successfully carried out using the CompactDaq system via NI Max test panel on the SEL 787 protection relay