DC power grid voltage stability control method based on transient electric quantity
A control method and voltage stabilization technology, applied in the field of DC power grid voltage stability control based on transient power, can solve problems such as weakening the dynamic stability of DC voltage and low inertia of DC power grid
Active Publication Date: 2021-03-02
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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Problems solved by technology
[0003] However, due to the low inertia of the DC power grid and the negative damping caused by the distributed power supply and the load keeping the power constant for a short time after being disturbed, the dynamic stability of the DC voltage will be weakened.
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Embodiment 1
[0142] The present invention builds such as in Matlab / Simulink environment figure 2 The simulation model of the multi-terminal flexible DC grid is shown. On the AC grid side, the power frequency three-phase AC power supply is filtered and transformed to connect to the VSC 1 The converter is connected to the DC grid, and the capacitor C is connected in parallel dc The voltage across both ends represents the DC bus voltage. The load side is connected to the converter VSC with constant power control 2 , to ensure that the connected load exhibits constant power characteristics. During the simulation, the wind power generation system is regarded as an equivalent unit. The basic parameters of the simulation model are shown in Table 1.
[0143] Table 1 Model parameters
[0144]
[0145] From equations (7) and (8), it can be seen that when the load suddenly decreases, ΔP L CPL CPLmax increase, the stability of the system is improved, and stable operation is maintained; when...
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The invention discloses a DC power grid voltage stability control method based on transient electric quantity. The DC power grid voltage stability control method comprises the following steps of: establishing a multi-port direct-current microgrid model to obtain a droop control equation, a system loop voltage, a node current equation and a load power equation; calculating a damping coefficient alpha according to a state differential equation of the multi-port direct-current microgrid model, and judging whether the damping coefficient alpha meets a specified stability criterion or not; in direct-current voltage droop control, designing an improved droop control coefficient, and providing additional transient electric quantity by adjusting power control of an energy storage side converter, so as to increase accumulated electric quantity of a power supply side, and increase dynamic stability margin of a system; and giving an additional electric quantity control coefficient kQ, and adjusting the kQ to enable the kQ to meet constraint conditions, thereby ensuring that the provided control can provide positive damping for the system. According to the DC power grid voltage stability control method, the voltage droop control coefficient of the energy storage converter is improved according to the stability criterion, so that the energy storage converter generates constant positive additional transient electric quantity on the power supply side, and the transient stability margin is effectively increased.
Description
technical field [0001] The invention relates to the technical field of DC power grid transient stability control, in particular to a DC power grid voltage stability control method based on transient power. Background technique [0002] The distribution network is an important part of the power system. The distribution network constructed in the form of DC can not only simplify the access mode of power supply and load at each end, but also avoid reactive power and frequency problems. Compared with the AC grid, the distributed power generation is connected to the DC grid, the conversion device is simplified, the DC-AC inverter link is omitted, and there is no need to pay attention to frequency fluctuation, reactive power compensation, and power angle swing, and the system operation is more stable. Not only that, the increasing demand for DC loads has also promoted the development of flexible DC grids, and the system operation control technology of DC grids is gradually improvi...
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IPC IPC(8): H02J1/10
CPCH02J1/10
Inventor 付媛李浩张祥宇
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)