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Research on High Frequency Transient Overvoltage of Tightly-coupled Split Reactor Using in Parallel High-Voltage Circuit Breaker

Author: WuZuo
Tutor: LiZhenBiao
School: Huazhong University of Science and Technology
Course: High Voltage and Insulation Technology
Keywords: The high degree of coupling splitting reactor High-frequency transient overvoltage Modeling approach Lumped circuit Insulation
CLC: TM864
Type: Master's thesis
Year: 2011
Downloads: 15
Quote: 0
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Abstract

The high degree of coupling splitting reactor core equipment as a parallel high voltage circuit breaker, charged with the circuit breaker process parallel branch current and current limiting tasks. Prior expenses road arc extinction instant when the two branches of parallel high voltage circuit breaker arc extinction time inconsistency, the high degree of coupling splitting reactor suddenly suffered a steep wave amplitude up to 0.5 times the system phase voltage amplitude voltage invasion. Reactor internal in a steep wave action will produce high-frequency electromagnetic vibration, resulting in the reactor on the emergence of high-frequency transient over-voltage, high-frequency transient over-voltage circuit breaker chamber of the reactor internal insulation and the first open between the insulation will have a certain threat. To analyze the reactor split in the steep wave under the action of a high degree of coupling electric high-frequency transient over voltage on the reactor insulation, and circuit breaker first open ports insulation must informed the high-frequency transient voltage distribution in the reactor and their evolution over time of the change, and this need through the establishment of a reasonable description of the high-frequency equivalent circuit and solve a circuit to get, so this issue is the key to the high degree of coupling split reactor power reactors electromagnetic oscillations high frequency equivalent circuit was built mode as well as solving. To this end, this paper analyzes and compares the advantages and disadvantages of several existing winding high-frequency equivalent circuit modeling method, and the scope of application of the various methods of. Considering the accuracy of the model, solving the calculation of the amount of the circuit selected on the basis of the nature of high-frequency electromagnetic oscillations, lumped parameter modeling method to establish a high degree of coupling to split the high-frequency equivalent circuit of the reactor. Reactors in the establishment of a high degree of coupling to high-frequency equivalent circuit model of the process of splitting the reactor, this article by analogy - Zoom parallel straight multi-conductor system MTL the micro-yuan circuit and micro-element equation method, convenient access to the high degree of coupling split set the parameters of high-frequency circuit model and the lumped parameter circuit equations. In the process of the circuit equation solver on the one hand combined with the boundary conditions of the circuit breaker when breaking in non-equilibrium, force variables by separation - a method to remove the non-independent variable, and can describe the state of the entire high-frequency circuit of the variable most streamlined, the most simple form of the equation; On the other hand, is derived based on the trapezoidal rule, large-scale numerical solution of differential equations, and the method error correction to ensure accuracy more substantial increase in the efficiency of the equation solver. In addition, in the high-frequency circuit parameter calculation process, we deduce winding stray capacitance calculation based ring charge potential equation, to overcome the problem is difficult to calculate the hollow reactor stray capacitance parameters. Applications derived modeling and solving methods, calculated 12kV drum hollow high degree of coupling splitting reactor prototype in steep waves under high-frequency transient overvoltage. By analysis of over voltage distribution found, non-balanced opening off the moment in the way earlier expenditure, 12kV high coupling degree split between electrically reactor cylindrical insulating most dangerous place in the reactor height 55% -85% region, and the electrically reactor turns the most dangerous area in between the insulation near the line turns at both ends of the range of 5 turns. By splitting the reactor 12kV high degree of coupling the end of the non-ground branch voltage oscillation found, the reactor voltage at the end of oscillation frequency of 2MHz, an oscillating voltage can reach up to 1.5 times the phase voltage amplitude, so the article speculated that the high degree of coupling split reactance fracture transient recovery voltage magnitude and rate of rise of the internal high-frequency electromagnetic vibration may cause the circuit breaker are moving in the direction of increasing development, and thus increase the burden of the first open fracture surface contact between the insulation.

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CLC: > Industrial Technology > Electrotechnical > High Voltage Engineering > Overvoltage and Its Protection > Internal Overvoltage
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