Abstract
With the development of ultra-high voltage (UHV) technology, hybrid reactive power compensation (HRPC) will be widely applied in the future. To study the mechanism by which HRPC influences the characteristics of circuit breakers in UHV transmission lines, this paper establishes an improved electromagnetic coupling transmission line model for out-of-phase and short-line faults. Based on the HRPC equivalent model, a simulation analysis was performed on the characteristics of the circuit breaker when a fault occurs. Using an equivalent lumped parameter circuit, the rate-of-rise of recovery voltage (RRRV) computational formula was deduced and computed. The RRRV variation in the circuit breakers in the system, with and without HRPC, was obtained. Given the circuit breaker interruption characteristics, the research results provide an analysis foundation and a theoretical basis for optimizing the HRPC parameters and selecting the arrangements of circuit breakers in an UHV transmission line.
Highlights
As long-distance, large-capacity, and low-loss power transmission lines are important for optimizing resources distribution, ultra-high voltage (UHV) transmission technology has become the development focus of the power industry [1,2]
Hybrid reactive power compensation (HRPC) with series compensation and a stepped controlled shunt reactor is an ideal solution to the challenges, as it addresses both the increase in transmission power and the frequent adjustment of reactive power
When the circuit breakers interrupt the UHV transmission lines installed with the HRPC, if the fault lines are relatively long or the compensation capacitance cannot be bypassed in minimum operation mode, fault currents may show low frequency oscillation, high amplitude, and DC bias
Summary
As long-distance, large-capacity, and low-loss power transmission lines are important for optimizing resources distribution, ultra-high voltage (UHV) transmission technology has become the development focus of the power industry [1,2]. Among the switching electrical equipment, as the core of GIS (gas insulated switchgear), the circuit breaker has taken the responsibilities of closing under normal conditions, interrupting load current, short circuit current, out-of-phase current, and so on Since both the inductance and the capacitance are energy storage components in power systems, a transient process occurs when the operation states change due to normal operations or faults handling. The mechanism by which the short circuit current with low frequency oscillation influences the interrupting process of the circuit breakers in the UHV power system with the installation of HRPC should be studied in detail with quantitative computation. When the circuit breakers interrupt the UHV transmission lines installed with the HRPC, if the fault lines are relatively long or the compensation capacitance cannot be bypassed in minimum operation mode, fault currents may show low frequency oscillation, high amplitude, and DC bias. This paper provides theoretical support for the configuration of HRPC and guarantees the interrupting process of circuit breakers, which is of great practical significance to the safety and stability of power systems
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