Optimization control method suitable for UHVDC commutation failure fault recovery

A fault recovery and commutation failure technology, applied in the direction of power transmission AC network, circuit device, reducing/preventing power oscillation, etc., can solve the problems of end AC system power shortage, commutation failure, equipment damage, etc., and achieve the suppression of UHVDC The effect of system commutation failure failure recovery subsequent commutation failure, avoiding DC current control overshoot, and alleviating the degree of DC current oscillation

CN113098045AActive Publication Date: 2021-07-09HEFEI UNIV OF TECH +2
5 Cites 4 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2021-07-09

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The invention discloses an optimization control method suitable for UHVDC commutation failure fault recovery. The method comprises the following steps: 1, acquiring a DC voltage, a DC current, a converter turn-off angle and a bus phase voltage of an AC system at an inverter side of a UHVDC system in real time; 2, constructing dynamic current margin control by using a difference value between a rectification side-direct current instruction value and an inversion side direct-current measurement value and a slope of a current margin function; and 3, after the fault is cleared, through the inverter side converter, adopting constant current control to make the dynamic current margin control take effect, so that the current margin in the fault recovery process is reduced. According to the method, the direct-current control target in the UHVDC system low current recovery process can be determined, so that the probability of unstable recovery of the system caused by improper interaction of the rectification side constant current controller and the inversion side constant current controller is reduced, and the subsequent commutation failure generated in the UHVDC fault recovery process is effectively inhibited.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention relates to an optimized control method suitable for UHVDC commutation failure fault recovery, and belongs to the technical field of commutation failure suppression of high-voltage direct current transmission systems. Background technique

[0002] With the increasing demand for transmission capacity and transmission distance in the interconnection of the eastern and western power grids, the UHVDC system has obvious advantages in large-capacity, long-distance power transmission and power system networking, and has become an "AC-DC hybrid" An important part of the grid. UHVDC systems all use thyristors as commutation components, and need to rely on grid voltage to restore their own blocking capability. Therefore, the inverter side converter is vulnerable to commutation failure due to grid faults.

[0003] Since the suppression of the first commutation failure requires extremely high prediction response speed of the controller, it is difficu...

Examples

Embodiment Construction

[0033] In this embodiment, the UHVDC system is composed of rectification-side AC system, rectification station, DC transmission line, inverter station, and inverter-side AC system. The hierarchical access method is adopted, and the bipolar low-end converter is connected to the 1000kV AC system. , the bipolar high-end converter is connected to the 500kV AC system. The DC controller adopts the selective controller in the CIGRE bipolar standard test model, such as figure 1 As shown, it consists of a constant current controller on the rectifier side, a low-voltage current limiting controller, a dynamic current margin controller, a current deviation controller, a constant current controller on the inverter side, and a constant turn-off angle controller on the inverter side; Inverter side DC voltage U d_inv and DC current I d_inv , the measurement link adopts the first-order inertial function, which can not only reflect the response speed of the measurement equipment, but also fil...