On-grid/off-grid seamless switching control method for photovoltaic micro grid

A control method and seamless switching technology, applied in photovoltaic power generation, electrical components, circuit devices, etc., can solve the problems of continuous impact of user power supply and difficulty in seamless switching, achieve fully automatic reliable switching, and reduce transient transition time, the effect of reducing shock

Inactive Publication Date: 2019-10-15
STATE GRID XINJIANG ELECTRIC POWER CO URUMQI ELECTRIC POWER SUPPLY CO +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the frequent switching of the control loop has a negative impact on the continuity of the user's power supply, especially when the microgrid structure is complex or the load has special requirements for uninterrupted power supply, it is more difficult to achieve seamless when the microgrid is connected to the grid. to switch

Method used

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  • On-grid/off-grid seamless switching control method for photovoltaic micro grid
  • On-grid/off-grid seamless switching control method for photovoltaic micro grid
  • On-grid/off-grid seamless switching control method for photovoltaic micro grid

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Effect test

Embodiment 1

[0046] Energy storage units, photovoltaic power generation units, local loads, energy management systems, microgrid grid-connected synchronous protection devices based on virtual synchronous control (VSG).

[0047] The invention discloses a control method for seamless switching between grid-connected and off-grid photovoltaic microgrids, which realizes smooth switching from grid-connected to off-grid and from off-grid to grid-connected.

[0048] When the photovoltaic microgrid is scheduled to operate from grid-connected to off-grid, in order to reduce the impact of the transition process of on-grid / off-grid switching on the power quality and reduce the transient transition time, before the switching test, the energy management system of the microgrid , to pre-adjust the charging and discharging power of the energy storage, so that the power of the connection line between the microgrid and the main grid is within an acceptable range, and the on / off grid switching operation is pe...

Embodiment 2

[0061] The invention discloses a control method for seamless switching between grid-connected and off-grid photovoltaic microgrids, which realizes smooth switching from grid-connected to off-grid and from off-grid to grid-connected.

[0062] 1. When the photovoltaic microgrid is scheduled to operate from grid-connected to off-grid, in order to reduce the impact of the transition process of on-grid / off-grid switching on the power quality and reduce the transient transition time, before the switching test, the micro-grid energy The management system pre-adjusts the charging and discharging power of the energy storage, so that the power of the connection line between the microgrid and the main grid is within an acceptable range, and performs on / off grid switching operations.

[0063] When the photovoltaic microgrid is planned to switch from grid-connected to off-grid, the main implementation process includes the following steps:

[0064] (1) The background data of the energy mana...

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Abstract

The invention discloses an on-grid/off-grid seamless switching control method for a photovoltaic micro grid. By controlling the power of a tie line at a specified target value, the transient transition time is reduced, and smooth switching from an on-grid mode to an off-grid mode is realized. Full-automatic and reliable switching from an off-grid mode to an on-grid mode is realized by using a micro grid on-grid synchronization protection device. For operation from an on-grid mode to an off-grid mode, the method includes the following steps: (1) refreshing the background data of an energy management system; (2) calculating and acquiring a required active power adjustment compensation value; (3) calculating the adjustable potential range of the external exchange power of an energy storage unit; (4) controlling the power of a tie line at a constant value; and (5) adjusting the power of the tie line to a target value. For switching from an off-grid mode to an on-grid mode, the method includes the following steps: S1, the micro grid operates stably in an off-grid operation mode; S2, the energy management system receives a micro grid grid-connection closing instruction issued by a dispatcher; S3, the synchronization protection device judges the grid connection conditions; and S4, the switching from an off-grid mode to an on-grid mode is completed.

Description

technical field [0001] The invention relates to a photovoltaic micro-grid switching control method, which is specifically used for controlling the switching of the photovoltaic micro-grid from grid-connected to off-grid and from off-grid to grid-connected. Background technique [0002] As an advanced structural form of distributed power generation, microgrid can effectively organize a variety of distributed power sources, loads, and energy storage. It can also run independently off the grid. With the development of micro-grid technology, its power source type, grid-connected mode, energy storage configuration and load composition are complex and changeable. How to control the smooth and seamless switching of the micro-grid system between on-grid and off-grid has become an urgent technology to be solved. difficulty. It has been proposed in the literature that PQ control should be used when the micro power supply is connected to the grid, and droop control should be used whe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/24H02J3/48
CPCH02J3/24H02J3/383H02J3/48Y02E10/56
Inventor 向红伟王伟常喜强王彤邢占礼韦徵刘彪刘新宇袁文海陈臻陈疆塔伊尔江·巴合依黄新民
Owner STATE GRID XINJIANG ELECTRIC POWER CO URUMQI ELECTRIC POWER SUPPLY CO
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