Electronic anti-islanding protection testing device and method for photovoltaic grid-connected inverter

Abstract

According to an electronic anti-islanding protection testing device and method for a photovoltaic grid-connected inverter, an electronic anti-islanding device is connected between the photovoltaic grid-connected inverter to be tested and a large power grid in series, energy is absorbed from the power grid side to stabilize a direct-current side voltage, an input side is inverted to form a voltage source, after the photovoltaic grid-connected inverter to be tested detects a voltage source with a stable frequency, voltage output is tracked in real time, a calculation module in the load simulator carries out sampling to obtain an actual power value output by the photovoltaic grid-connected inverter to be tested, and a power instruction calculation module carries out calculation to obtain a power reference value needing to be adjusted. Then an input side self-adaptive PI controller carries out adjustment to obtain simulated R, L and C loads which are matched with the power output by the photovoltaic inverter to be tested, after power matching, the power flow of the photovoltaic grid-connected inverter to be tested flows to the electronic anti-islanding input side, and the output side feeds energy back to a power grid through a four-quadrant control strategy. And the automatic test of the anti-islanding protection function of the photovoltaic grid-connected inverter is realized.

Description

technical field [0001] The invention relates to photovoltaic grid-connected inverter technology, in particular to an electronic anti-islanding protection test device and method for photovoltaic grid-connected inverters. Background technique [0002] In recent years, distributed new energy generation has maintained a continuous growth trend due to its economy and effectiveness, and its access to the distribution network has also brought a series of problems to the power grid, among which "island" is currently the most widely studied one of the subjects. Once an island occurs, it may cause problems such as personal safety, power quality, and protection malfunction. According to the requirements of relevant national standards, the inverter integrated into the distribution network with a voltage level of 10KV and below should have the protection function of anti-islanding effect. If the grid power supply is interrupted, the grid-connected inverter shall stop supplying power to...

AI Technical Summary

Problems solved by technology

Passive detection technology judges islands based on whether parameters such as voltage, frequency, active power, and reactive power exceed the limits. Its main advantage is that it will not affect power quality, but there is a large detection blind spot; active detection technology It is to inject disturbances into the amplitude, frequency, and phase of the inverter current, and when the islanding occurs, the relevant parameters of the grid-connected point will change to determine the islanding state. Its main advantage is to reduce or even eliminate the blind zone, but the resulting It is to deteriorate the power quality of the grid, and even affect the stability of the grid. At present, the anti-islanding detection algorithm of photovoltaic grid-connected inverters mainly adopts active and passive detection methods

The anti-islanding protection of photovoltaic grid-connected inverters mainly uses adjustable parallel RLC simulated loads for laboratory tests. This test method is not only complicated in the test process, but also requires harsh test conditions.

Moreover, this device is not only bulky, expensive, complicated to operate, time-consuming, but also consumes a large amount of electric energy, which cannot meet the requirements of energy saving and environmental protection.

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