Method and apparatus for islanding detection for grid tie converters

A technology of islanding effect and converter, applied in the direction of instrument, measuring power, measuring device, etc., can solve the problem of not ensuring the accurate identification of unplanned islanding effect of grid-connected converters

Inactive Publication Date: 2014-09-17
ROCKWELL AUTOMATION TECH
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Problems solved by technology

However, conventional techniques are far from ensuring accurate identification of unintended islanding in grid conver...

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  • Method and apparatus for islanding detection for grid tie converters
  • Method and apparatus for islanding detection for grid tie converters
  • Method and apparatus for islanding detection for grid tie converters

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Embodiment Construction

[0015] Referring now to the drawings, several embodiments or implementations are described below in conjunction with the drawings, wherein like reference numerals refer to like elements throughout, and wherein various components are not necessarily drawn to scale.

[0016] The detection of unplanned islanding effect is an important function of grid-connected converters to reduce or avoid damage or deterioration of system equipment and ensure or benefit the safety of maintenance and engineering personnel. Various techniques for detecting islanding have been proposed previously, including reactive power protection and active methods using grid-connected inverters and external devices. Reactive power protection techniques utilize voltage and frequency relays for anti-islanding protection by measuring electrical changes at the point of common coupling (PCC) and detecting conditions indicative of islanding. In some cases, however, reactive power scheme protection cannot detect isla...

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Abstract

Methods and apparatus are presented for unintentional islanding detection for grid tie converters in which the phase angle disturbance is introduced by modification of grid side converter switching control signals and a mismatch of reactive power between generation and the grid load is formed upon the occurrence of unintentional islanding, where the applied phase disturbance is determined according to two pre-defined curves to form an equivalent positive feedback at different frequencies to prevent the converter from forming an island at a new stable frequency after the grid is disconnected.

Description

Background technique [0001] Power conversion systems are used to convert electrical energy from one form to another. Grid-tie converters may be used in a variety of situations where power is converted from one form to provide power to a load and / or grid. For example, grid-connected converters are used to interface fuel cells, solar cells, wind power systems, batteries and other energy storage systems to the power grid. These converters are generally capable of regenerative operation, where grid power can be converted to DC power for charging a battery, or DC battery power can be converted to provide AC power to the grid. An islanding effect is a situation in which a portion of a regional power system or electricity supply (EPS) is energized by only one or more local EPSs through associated points of common connection or common coupling (PCC), while the regional EPS This part is electrically isolated from the rest of the area EPS. Islanding effects may be planned or unplanne...

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Application Information

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IPC IPC(8): G01R31/00H02J3/38
CPCH02J3/386H02J2003/388H02J3/382H02J3/388H02J2300/28H02J3/381Y02E10/76
Inventor 袁振环张绍峰卢海辉韦立祥拉塞尔·J·克尔克曼理查德·洛卡泽维斯基艾哈迈德·穆罕默德·赛义德·艾哈迈德罗伯特·J·布雷茨曼
Owner ROCKWELL AUTOMATION TECH
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