Photovoltaic power station low voltage ride through detecting system in high altitude area

Abstract

The invention provides a photovoltaic power station low voltage ride through detecting system in a high altitude area. The photovoltaic power station low voltage ride through detecting system comprises a power grid, a power grid side transformer, a testing unit, a photovoltaic side transformer, a tested photovoltaic unit and an automatic detecting control system. The automatic detecting control system comprises a monitoring module monitoring a tested unit, a control module achieving automatic control, and a processing module analyzing detected data. Full-automatic design is adopted in the system control, the system automatically selects the matched reactive resistance combination and simulated failure time and adjusts a tapping switch to the corresponding position to finish reactive resistance matching, selects the simulated grid fault type and switches the position of a single-phase disconnecting switch to finish grid fault type matching according to the voltage drop depth and the simulated failure type input by a background tester, the low voltage ride through test is finished, the hardware protection function and the software protection function of the whole set of system can be matched, the self-diagnosis function is complete, and the stability is good.

Description

technical field [0001] The invention relates to a system in the field of grid-connected detection of photovoltaic power plants, in particular to a low-voltage ride-through detection system for photovoltaic power plants in high-altitude areas. Background technique [0002] With the development of the photovoltaic industry, especially in the western region of my country, which has a vast territory and abundant sunshine resources, the photovoltaic industry is developing rapidly, and the proportion of photovoltaic power generation in the power grid is constantly increasing. When the power grid fails and the voltage drops, if the large-capacity photovoltaic grid-connected power station does not have the low voltage ride through (Low Voltage Ride Through, LVRT) capability, it will have a significant impact on the stability of the power system. Therefore, China has promulgated the State Grid Enterprise Standard Q / GDW617-2011 "Technical Regulations for Connecting Photovoltaic Power ...

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Problems solved by technology

[0007] (2) The low-voltage ride-through detection device of plain type mobile photovoltaic power station generally adopts the form of passive reactance voltage division, but due to the limitation of equipment installation space, the detection device cannot be equipped with many reactors, or cannot be configured to replace the reactor tap wiring Switches, etc., generally use manual replacement of the reactor tap wiring to change the reactor parameters of the main circuit

Manually change the wiring of the fault point to simulate the fault of the power grid, the steps are cumbersome, time-consuming, and have certain potential safety hazards

Regardless of manually modifying the reactance parameters or manually modifying the simulated grid fault mode, the operation can only be performed after the photovoltaic inverter under test stops running, which increases additional detection time and is not conducive to the improvement of the overall detection efficiency.

In addition, the equipment selection or installation of the low-voltage ride-through detection device of the plain mobile photovoltaic power station cannot meet the high-altitude electrical insulation requirements

[0008] (3) The low-voltage ride-through detection system of the fixed photovoltaic inverter is not limited by the installation space, so multiple reactor combinations can be used to adjust the main circuit reactance parameters by installing multiple switches or on-load tap changers, and through Multiple switch combinations are used to realize the switching of simulated power grid fault types, but the cost of the entire system is high, the floor space is large, and the equipment is installed in a fixed location and cannot be moved, so it is not suitable for photovoltaic power station detection

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