Island protection method based on low-voltage distributed photovoltaic access management and control system

A distributed photovoltaic and management and control system technology, applied in the direction of reducing/preventing power oscillation, electrical components, single-network parallel feeding arrangement, etc., can solve problems such as large detection blind area, small detection blind area, and influence on power quality

Pending Publication Date: 2022-07-29
SHANDONG ELECTRICAL ENG & EQUIP GRP
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The passive islanding detection method is easy to implement and does not affect the power quality, but when the inverter output power is basically balanced with the local load, the detectio

Method used

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  • Island protection method based on low-voltage distributed photovoltaic access management and control system
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  • Island protection method based on low-voltage distributed photovoltaic access management and control system

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Embodiment 1

[0025] This embodiment discloses an island protection method based on a low-voltage distributed photovoltaic access control system, such as figure 1 As shown in the figure, the low-voltage distributed photovoltaic access management and control system includes distribution transformers, intelligent gateways, branch boxes, low-voltage intelligent circuit breakers, inverters, and photovoltaic modules, so as to realize the safe access and controllability of low-voltage distributed photovoltaics. Among them, the low-voltage intelligent circuit breaker is installed at the low-voltage distributed photovoltaic access point (public connection point), and has functions such as real-time monitoring of the voltage, current, power, and load of the photovoltaic grid connection point, as well as island protection, over / under voltage protection, etc. The intelligent gateway collects the data collected by each low-voltage intelligent circuit breaker, and can monitor, analyze and control the ope...

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Abstract

The invention provides an islanding protection method based on a low-voltage distributed photovoltaic access management and control system, and the method comprises the steps: taking a voltage frequency swing range delta f and a voltage amplitude swing range delta U within a set time T as the determination of an islanding protection mode, and if the absolute value of the voltage frequency swing range is greater than or equal to 0.2 Hz or the absolute value of the voltage amplitude swing range is greater than or equal to 20V, starting the islanding protection mode; if yes, the passive island detection criterion is established, the low-voltage intelligent circuit breaker judges that the island effect occurs, and the grid-connected point is cut off immediately and reported to the intelligent gateway; if the absolute value of the voltage frequency swing range is smaller than 0.2 Hz, active island detection is started, and disturbance is injected to the output current of the inverter. On the premise of considering electricity utilization safety and electric energy quality, secondary protection for preventing the islanding effect is effectively achieved, and it is ensured that a power grid is safer and more reliable.

Description

technical field [0001] The invention relates to the technical field of distributed power generation, in particular to an island protection method based on a low-voltage distributed photovoltaic access control system. Background technique [0002] In recent years, with the rapid growth of energy demand and the over-exploitation of non-renewable energy, my country's photovoltaic power generation has fully entered the stage of large-scale development. In a grid with distributed photovoltaic grid-connected access, the islanding effect is defined as: when the grid loses voltage, the grid-connected photovoltaic power generation system still maintains the state of continuing to supply power to a certain part of the grid in the lost voltage grid. The islanding effect will not only cause harm to the power grid load or personal safety, but also affect the power quality. The specific manifestation is that the power supply voltage and frequency in the power island area are unstable, whi...

Claims

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Application Information

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IPC IPC(8): H02J3/38H02J3/24H02J13/00
CPCH02J3/381H02J3/388H02J3/241H02J13/0004H02J2300/24
Inventor 吴悠付志达李磊刘恒涛张猛李建时培征刘娟杜旭明
Owner SHANDONG ELECTRICAL ENG & EQUIP GRP
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