AC-DC hybrid system transient stability analysis method considering commutation failure
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A transient stability analysis, AC-DC hybrid technology, applied in AC network circuits, power transmission AC networks, circuit devices, etc. Effect
Active Publication Date: 2021-01-01
NORTH CHINA ELECTRIC POWER UNIV (BAODING) +1
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[0006] The disadvantage of the above-mentioned prior art is that when the AC system fails in the AC system and causes commutation failure on the inverter sid...
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[0026] The preferred specific implementation method of the transient stability analysis method of the AC / DC hybrid system considering commutation failure of the present invention is:
[0027] Aiming at the AC / DC hybrid system with grid commutation HVDC transmission line, the transient energy function with DC line is constructed, and the transient energy function of the AC / DC hybrid system is performed under the scenario of commutation failure on the DC inverter side caused by an AC fault. State stability analysis, including:
[0028] Firstly, by equating the DC converter station to the dynamic load on the corresponding converter bus, the network structure preserving model of the AC-DC hybrid system is established, and its energy function is constructed through the first integration;
[0029] Then, the transient energy function of the system after a fault is approximately calculated by adopting the trapezoidal integral path, and a transient stability criterion based on the ener...
specific Embodiment
[0100] Step 1: Construction of network structure preservation model of AC / DC hybrid system
[0101] For an AC / DC hybrid system with n nodes and l DC lines (LCC-HVDC), where i=1, 2,..., m nodes are connected to generators. The synchronous generator is represented by a constant E'q, taking into account the voltage characteristics of the load, ignoring the resistance of the high-voltage line, and equating both ends of the DC line as the injected power of the corresponding busbar, and obtaining an equivalent model based on the system network structure maintenance model ,Such as figure 1 shown.
[0102] In the center of inertia (Center of Inertia, COI) reference coordinates, the system equation is:
[0108]In the formula: i=1,2,···,m; θi, ωi are the power angle and angular velocity of the i-th synchronous generator relative to the center of inertia (COI) respectively; Ui, φi...
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Abstract
The invention discloses an AC-DC hybrid system transient stability analysis method considering commutation failure, and the method comprises the steps: building a network structure maintenance model of an AC-DC hybrid system for the AC-DC hybrid system comprising a power grid commutation type high-voltage DC transmission line through enabling a DC converter station to be equivalent to a dynamic load on a corresponding commutation bus; constructing an energy function through first integration; secondly, approximately calculating a transient energy function of the system after the fault by adopting a trapezoidal integral path, proposing a transient stability criterion based on the energy function, and quickly calculating the limit clearing time of the system by utilizing a dichotomy; finally, building an improved IEEE-39 node alternating current and direct current hybrid system, and verifying the correctness of the theoretical analysis method through simulation. When an alternating current system of the alternating current and direct current series-parallel system breaks down and causes commutation failure on the inversion side of a direct current line, transient stability margin analysis can be rapidly carried out.
Description
technical field [0001] The invention relates to a transient stability analysis technology for an AC / DC hybrid system, in particular to a transient stability analysis method for an AC / DC hybrid system considering commutation failure. Background technique [0002] At present, large primary energy bases and load centers are generally distributed in reverse. In order to optimize resource allocation and improve energy utilization efficiency, Line Commutated Converter High Voltage Direct Current (LCC-HVDC) has developed rapidly due to its advantages in long-distance and large-capacity power transmission. The AC-DC hybrid system presents the characteristics of high DC ratio and large capacity in the grid structure. When the AC system in the vicinity of the converter station on the inverter side of the DC line fails, it will cause commutation failure on the DC inverter side at the same time, resulting in a short-term and large-scale shift of the power flow, which seriously threaten...
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