Abstract
The testing approach is facing many difficulties regarding the actual implementations in the modern smart power grids. One of these challenges is the testing of hardware devices such as protective relays, PMUs, and smart meters before its final deployment to the power grid. One way to overcome this is the real-time simulation of power grid. The hardware-under-test (HuT) is plugged to a real-time simulator via signal conditioning circuit (SCC). SCC is an interface circuit involving power amplifier and measurement sub-circuit between the real-time power grid simulator and the HuT. In this chapter, some advanced developed techniques and approaches will be presented.
TopTestability
Protection System Reliability and Testability require in part that the protection system be designed for high functional reliability and in-service testability commensurate with the safety function to be performed. They also require a design that permits on-line periodic testing of the functioning of the protective system.
The testing of protection schemes faces many problems. Since the main function of protection equipment is taken into consideration under operation during system fault conditions, and it cannot readily be tested under normal conditions (Relay testing and commissioning, Chapter Online). This situation is aggravated by increasing the complexity of protection schemes and use of relays containing software.
Type tests are required to prove that a relay meets the published specification and complies with all relevant standards. Since the principle function of the protection relay is to operate correctly under abnormal power conditions, it is essential that the performance be assessed under such conditions. Comprehensive type tests simulating the operational conditions are therefore conducted at the manufacturer’s works during the development and certification of the equipment.
Different testings that can be carried out by the developed testing system are as follows (Chafai, M., Bentarzi, H., & Ouadi, A., 2014):
Key Terms in this Chapter
Signal Conditioning Circuit (SCC): In electronics, signal conditioning is the manipulation of an analog signal in such a way that it meets the requirements of the next stage for further processing. In an analog-to-digital converter application, signal conditioning includes voltage or current limiting and anti-aliasing filtering.
Total Harmonic Distortion (THD): A total harmonic distortion is a measurement of the harmonic distortion presents in a signal and is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency. Distortion factor, a closely related term, is sometimes used as a synonym.
Hardware-Under-Test (HuT): In power hardware in the loop (PHIL) simulations, a real-time simulated power system is interfaced to a piece of hardware, usually called hardware under test (HuT). ... Stable operation of the entire system, along with the accuracy of simulation results are the main concerns regarding a PHIL simulation.
Real-Time Simulator: Refers to a computer model of a physical system that can execute at the same rate as actual “wall clock” time.