Optimized testing of modern protection equipment using transient simulation

Throughout the years different testing tools have been used successfully for all types of relays. Traditional methods like current ramping applied in many cases. These traditional methods work well with classical protection functions and equipment. But the requirements on the protection system are changing and so does the protection system; examples: (1) Increasing complexity of multifunctional equipment (2) Implementation of adaptive or intelligent protection functions (3) Growing use of individual designed protection functions and logical functions (4) Use of IEC 61850 and growing use of communication between protection lEDs. These changes allow optimization of the testing strategy. In this paper the new requirements on testing are analyzed. Based on this it is shown that testing using transient simulation is a solution. The requirements on the transient simulated signals caused by different protective functions are pointed out. Additionally the requirements on network data and models used for simulation are analyzed. The advantages of testing using transient simulation are presented for some applications. It is shown that the new method covers a larger part of the commissioning and design process. Therefore testing using transient simulations is able to find more malfunctions in the protection system. The logical procedure of systematically identifying malfunctions is demonstrated. Examples for an optimized workflow of protection testing using transient simulations are presented, although the discussed method could be used in a traditional workflow. The advantages of an adapted workflow are pointed out. The integration of transient simulation testing in a testing strategy is shown and the complete service concept of the protection system (including repairs, testing, maintenance and refurbishment) is discussed.