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A photovoltaic microgrid-contained on-line overvoltage protection method based on equivalent Thevenin circuit

An equivalent circuit and overvoltage technology, applied in the field of new energy access protection and control, can solve problems such as poor regulation, avoid frequent shutdowns, simplify the correction process, and improve consumption.

Inactive Publication Date: 2019-01-18
CHINA SOUTHERN POWER GRID COMPANY +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in the existing operation scheme, the droop control constant is usually a fixed value, which is only used to improve the active power output of the system in extreme cases, and the regulation is poor

Method used

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  • A photovoltaic microgrid-contained on-line overvoltage protection method based on equivalent Thevenin circuit
  • A photovoltaic microgrid-contained on-line overvoltage protection method based on equivalent Thevenin circuit
  • A photovoltaic microgrid-contained on-line overvoltage protection method based on equivalent Thevenin circuit

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Embodiment Construction

[0023] The technical solutions and beneficial effects of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0024] Such as figure 1 Shown is a flowchart of an online overvoltage protection method for a photovoltaic microgrid based on an equivalent Thevenin circuit in the present invention, including the following steps:

[0025] 1. Obtain historical photovoltaic output data with a sampling frequency of 5 minutes, and build a network based on IEEE 33 nodes connected to photovoltaic power plants.

[0026] 2. Start the simulation operation, and detect the voltage, current and power of the photovoltaic access point at two adjacent moments.

[0027] Detect the output power of the photovoltaic system according to the fixed sampling frequency, and calculate the change rate of two adjacent output powers:

[0028]

[0029] Among them, P out (k) represents the external output power of the photovoltaic system at time k, R pv (k...

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Abstract

The invention discloses a photovoltaic microgrid-contained on-line overvoltage protection method based on an equivalent Thevenin circuit. The method comprises the following steps: detecting actual output power and current voltage data of a photovoltaic system; The variation rate of the output power of the photovoltaic system at two adjacent sampling times is compared, and the Thevenin equivalent circuit of the system is updated on line when the variation rate is greater than the threshold value. Calculating a power limit value corresponding to the safe access voltage and a power voltage regulation coefficient according to the preset access voltage control limit value of the photovoltaic system; The actual voltage of the access point of the photovoltaic system is detected again; The outputpower of the photovoltaic inverter is obtained by numerical calculation of the detection voltage, and the external output power of the photovoltaic system is changed. This method can realize the friendly access of photovoltaic system and avoid the generation of photovoltaic overvoltage to the maximum extent while ensuring the maximum access of photovoltaic power in practical operation. The controlmode has good economy and security.

Description

technical field [0001] The invention belongs to the technical field of new energy access protection control, and in particular relates to an online overvoltage protection method for a photovoltaic microgrid based on an equivalent Thevenin circuit. Background technique [0002] In today's society, photovoltaic power generation has gradually become an important part of the global energy system. However, the output power of photovoltaic output is mainly directly affected by external weather conditions, and the changing radiation intensity and temperature will directly lead to severe fluctuations in the voltage of photovoltaic access points. Obviously, the fluctuation of the output power of photovoltaic power station and the voltage of the access point will have a negative impact on the stable operation of the power grid. Therefore, in recent years, many scholars have proposed corresponding protection and control strategies for the problem of photovoltaic access. Using the corr...

Claims

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Application Information

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IPC IPC(8): H02J3/38H02H9/04G05F1/67
CPCG05F1/67H02J3/383H02H9/04Y02E10/56
Inventor 陈宏山余江丁晓兵张弛徐光福李正红陈俊魏承志李岩李捷姜淼
Owner CHINA SOUTHERN POWER GRID COMPANY