A double-terminal acceleration protection method for DC distribution network
A DC distribution network, double-terminal technology, applied in the direction of automatic disconnection emergency protection device, emergency protection circuit device, emergency protection data processing device, etc., can solve the problem of reducing fault removal time, etc., to achieve perfect line protection, increase speed dynamic effect
Active Publication Date: 2022-07-29
XIAN UNIV OF TECH
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[0003] The present invention provides a dual-terminal acceleration protection method for DC distribution network, which solves the requirement of the existing DC distribution network on the quickness of protection, and can effectively increase the speed of fault removal, thereby reducing the fault removal time
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Embodiment 1
[0053] Built in MATLAB / SIMULINK such as Figure 5 The topological structure model of the four-terminal ring network DC power distribution system shown, the model is constructed by four MMC converters, connecting four lines, and installing front acceleration devices on the source side of each line, which are AR12, AR21, AR13, AR31, AR24, AR42, AR34, AR43, each front acceleration device has a corresponding DC circuit breaker. The installed DC circuit breaker is the current mainstream hybrid DC circuit breaker. The length of the DC distribution line is 100km. The DC voltage U dc It is ±100kV and the sampling frequency is 10kHz. The relevant parameters of the ring network distribution network are shown in Table 1. The frequency domain model (Frequency Dependent (Phase) Model) in PSCAD is used for the circuit, and the circuit parameters are shown in Table 2. shown.
[0054] Table 1 Four-port DC distribution network parameter table
[0055]
[0056] Table 2 System line paramet...
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A double-terminal acceleration protection method for a DC distribution network disclosed by the invention proposes an acceleration protection scheme that meets the needs of practical engineering for rapidity from the point of view of quickness. It consists of transient fault identification, permanent fault type and fault area identification. In this paper, in order to reduce the misoperation caused by the first acceleration protection, two startup criteria are proposed to avoid steady state and some non-fault conditions, which effectively improves the selectivity and ensures that the DC circuit breaker operates quickly within 1ms after the fault, and the commutation The power electronics in the device will not be damaged and will not latch up. After the 300ms de-isolation delay, after reclosing the DC circuit breaker and identifying the permanent fault, the voltage and current fault information after the reclosing can be used to accurately identify the fault type and fault area. This accelerated protection scheme helps to improve the DC power distribution. Engineering line protection.
Description
technical field [0001] The invention belongs to the technical field of DC distribution network relay protection, and relates to a double-terminal acceleration protection method for DC distribution network. Background technique [0002] Distributed power generation and energy storage technologies continue to break through, and the rapid increase in urban DC loads has led to earth-shaking changes in the “source, network, and load” of traditional distribution networks. At the same time, the shortage of urban power supply corridors has restricted the expansion of AC power distribution. line constraints. The medium voltage direct current (MVDC) network is easy to realize the access of distributed energy, and it is convenient to cooperate with the energy storage. Compared with the AC distribution network, the DC distribution network has outstanding advantages such as higher power transmission efficiency, better power quality, lower loss and less environmental pollution, which has...
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IPC IPC(8): H02H7/26H02H3/06H02H1/00
CPCH02H7/268H02H3/06H02H1/0092
Inventor 段建东李再男路文超
Owner XIAN UNIV OF TECH