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Chain type STATCOM interphase direct current voltage balance control method

A DC voltage and balance control technology, which is applied in flexible AC transmission systems, single-network parallel feeding arrangements, multi-phase network asymmetry reduction, etc., can solve complex calculations, affect DC voltage equalization control between phases, and DC voltage fluctuations And other issues

Pending Publication Date: 2020-10-20
YUNNAN POWER GRID CO LTD ELECTRIC POWER RES INST
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Problems solved by technology

However, the capacitors on the DC side of the chained STATCOM are independent of each other. Due to the differences in the parallel loss, switching loss, modulation ratio, and pulse delay of each H-bridge unit, the DC voltage of each H-bridge unit is unbalanced.
[0003] Existing research uses the method of zero-sequence voltage injection to realize the balance control of DC voltage between phases, but the calculation is too complicated
At the same time, when the grid voltage is asymmetrical, the negative sequence component in the grid voltage will affect the voltage equalization control of the DC voltage between phases, resulting in large fluctuations in the DC voltage and affecting the output of the chained STATCOM

Method used

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  • Chain type STATCOM interphase direct current voltage balance control method
  • Chain type STATCOM interphase direct current voltage balance control method
  • Chain type STATCOM interphase direct current voltage balance control method

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Embodiment Construction

[0023] Aiming at the star-connected chained STATCOM interphase DC voltage balance control, the present invention proposes a new phase-to-phase DC voltage control scheme. When the power grid is normal, the output power relationship of the chained STATCOM is deduced, and on this basis a simple The zero-sequence voltage calculation method; at the same time considering the influence of the negative-sequence component when an asymmetric fault occurs in the power grid, a power feed-forward control method is proposed, which calculates the active power generated by the negative-sequence voltage in real time, and forwards the power Feedback to solve the fluctuation of DC voltage between phases when the power grid is asymmetrical.

[0024] The different active power components in the three phases of the chained STATCOM can be described as:

[0025]

[0026] From the above formula, it can be found that the different active power components ΔP in the three phases k The magnitude of is...

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Abstract

The invention discloses a chain type STATCOM interphase direct current voltage balance control method. The method comprises: acquiring active power caused by chain type STATCOM three-phase unit difference; calculating active power generated by the negative sequence voltage in real time when an asymmetric fault occurs in the power grid; superposing the active power generated by the negative sequence voltage and the active power caused by the difference of the chain-type STATCOM three-phase units to obtain the active power required to be adjusted by the whole system; and calculating a zero-sequence voltage value required to be injected according to the active power required to be adjusted by the whole system and the zero-sequence voltage calculation formula. Based on a zero-sequence voltageinjection method, a simple zero-sequence voltage calculation method and a power feed-forward control method are provided for inter-phase direct-current voltage imbalance caused by H-bridge unit difference and negative-sequence components in power grid voltage, and inter-phase direct-current voltage imbalance fluctuation of a power grid under different working conditions can be effectively suppressed.

Description

technical field [0001] This application relates to the field of power electronics technology research, in particular to a chained STATCOM phase-to-phase DC voltage balance control method. Background technique [0002] Static Synchronous Compensator (STATCOM) has the functions of enhancing system stability, improving power flow and voltage distribution, and has been widely used in recent years. Among them, the STATCOM with chain structure has attracted a lot of attention because of its advantages of easy modularization, high reliability, low switching loss and small harmonic distortion. However, the capacitors on the DC side of the chained STATCOM are independent of each other. Due to the differences in the parallel loss, switching loss, modulation ratio, and pulse delay of each H-bridge unit, the DC voltage of each H-bridge unit is unbalanced. [0003] Existing research uses the method of zero-sequence voltage injection to realize the balance control of DC voltage between p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/18H02J3/48H02J3/26
CPCH02J3/18H02J3/48H02J3/26Y02E40/10Y02E40/50
Inventor 邢超李胜男奚鑫泽徐志何鑫刘明群郭成向川
Owner YUNNAN POWER GRID CO LTD ELECTRIC POWER RES INST
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