An islanding protection method for grid-connected photovoltaic systems based on double vector angles

A photovoltaic system, double vector technology, applied in the direction of photovoltaic power generation, emergency protection circuit device, single network parallel feeding arrangement, etc., can solve the problems of active power fluctuation, slow speed, etc., to improve performance, improve output power performance, overcome Effect of active power fluctuations

CN104269830BActive Publication Date: 2017-05-10DONGFANG ELECTRIC AUTOMATIC CONTROL ENG CO LTD
4 Cites 0 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2017-05-10

Smart Images

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

Abstract

The invention discloses an islanding protection method of a photovoltaic power generation system. The method is an active islanding protection technology based on dual vector angles. The voltage vector angle obtained before disturbance and the voltage vector angle obtained after disturbance are adopted by the technology, and disturbance components are extracted and blended in the Sandia islanding protection technology. The method not only improves the islanding protection performance of the photovoltaic system, but also overcomes the shortcoming of active power fluctuation caused by a traditional phase perturbation algorithm, and improves the output power performance of inverters in the normal operating process.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention relates to the fields of power electronics and photovoltaic power generation inverter control, in particular to an island protection method for grid-connected photovoltaic systems based on double vector angles. Background technique

[0002] With the increasing shortage of energy and the higher and higher requirements of users for the reliability of power supply, distributed power generation plays an increasingly important role in the power system. Solar photovoltaic (photovoltaic, PV) power generation system is very important in distributed power generation. One of the important power generation methods. The solar power generation system sends electric energy to the grid, which is called a grid-connected system. When the grid power supply trips due to a fault accident or power outage maintenance, the photovoltaic power generation system at each user end fails to detect the power failure state in time and cuts itself off from the mains ne...

Examples

Embodiment Construction

[0038] A method for islanding protection of a grid-connected photovoltaic system based on a double-vector angle of the present invention will be further described below in conjunction with the accompanying drawings.

[0039] The principle of the synchronous dq rotating coordinate system in the grid-connected control algorithm of the inverter is as follows: figure 1 As shown, the three-phase photovoltaic inverter control algorithm is based on the integrated grid voltage vector, that is, a The vector angle in the coordinate system is used to express the phase information of the three-phase voltage, and the current vector is the same. Therefore, the zero-crossing point of this angle is not different from the real zero-crossing point in the unidirectional inverter, but only shows that the A phase is the zero-crossing point at this time, and the other two phases are not zero-crossing points. The three-phase alternating current is converted into the direct current in the synchrono...