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Protective Relay Testing

Canadians have become addicted to electricity, its uses grow daily and because of this fast-paced growth, there is an ever-increasing interest in testing practices for protective relaying systems.

Since 1989, Pace Technologies Inc. is engaged in the testing, commissioning, and maintenance of high, medium and low voltage power systems. The electrical distribution system is the heart of a facilities operation. Acceptance testing is an ideal solution to determining if your equipment has been installed correctly. Pace Technologies technicians can provide the services required to ensure your new system has been installed correctly and will operate as designed. Pace Technologies technicians perform acceptance testing in accordance with the InterNational Electrical Testing Association (NETA) specifications while also referencing the manufacturers’ specifications.

The goal of testing relays is to maximize the availability of the protection and to minimize the risk of a misoperation. Using the best testing method is integral to a good testing philosophy. Finally, developing a plan for periodic testing assumes that a system is properly and comprehensively commissioned.

The following describes the recommended approach to relay testing and best practices:

  • Perform comprehensive commissioning testing at the time of installation. Use thorough checklists, simulations, laboratory testing, and/or field checks to verify the performance of the protection system, including inputs, outputs, and settings.
  • Monitor the relay self-test alarm contact in real-time via supervisory control and data acquisition (SCADA) or another monitoring system. If an alarm contact asserts, take immediate steps to repair, replace, or take corrective action for the alarmed relay.
  • Monitor potential relay failures not detected by self-tests. Specifically, these are logic inputs, contact outputs, and analog (voltage and current) inputs. Use continuous check of inputs (e.g., loss-of-potential logic) when available. If a secondary relay system is in place, compare the metering values between the primary and secondary systems.
  • Analyze event reports to root cause, and verify logic inputs and output contact operation. Use event reports as documentation to validate correct operation of the protection system.
  • Observe and act on all product service bulletins. Not every service bulletin requires action, but each bulletin should be evaluated. Upon request, the manufacturer can provide specific information or a secure website to track affected relays.

The relevance of acceptance testing is constantly growing along with the increasing number of relay providers and relay models. Depending on what needs to be tested, either a function-based or a simulation-based (black box) approach is the right option. In addition, it can be a challenge to handle the firmware updates that come with modern relays. Often new firmware is tested in the utility lab before it is applied to all the other devices in the field.

Safety at Pace Technologies Inc. unites Commitment, Responsibility and Pride for our Employees, Customers and the Environment. If you have questions about relay testing or any other electrical issue for your power system contact Pace Technologies Inc. today in Calgary at 403-508-0770; Edmonton at 780-450-0404; Fort McMurray at 780-743-4309; Kelowna, BC at 250-712-0091; and Santiago, Chile at (02) 2559-5669.

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