An adaptive longitudinal protection method for distributed power distribution network with inverter

An inverter-type distributed and distributed power supply technology, which is applied in the direction of emergency protection circuit devices, electrical components, single-network parallel feeding arrangements, etc., can solve problems such as difficult to balance selectivity and sensitivity, and achieve fast calculation speed The effect of high reliability and strong applicability

Active Publication Date: 2021-05-14
SOUTH CHINA UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in this grid-connected mode, the injection current of the distributed power supply is unknown to the protection devices at both ends of the line, which makes it difficult for conventional longitudinal protection to take into account its selectivity and sensitivity

Method used

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  • An adaptive longitudinal protection method for distributed power distribution network with inverter
  • An adaptive longitudinal protection method for distributed power distribution network with inverter
  • An adaptive longitudinal protection method for distributed power distribution network with inverter

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Embodiment

[0059] This embodiment takes figure 1 Take the distribution network shown as an example, where the line impedance is: 0.13+j*0.356Ω / km, and the line M-PCC 1 、PCC 1 -PCC 2 、PCC 2 -PCC 3 、PCC 3 The lengths of -N are: 2km, 1km, 3km, 2km; IBDG 1 , IBDG 2 , IBDG 3 The capacities are 2MW, 1MW and 3MW respectively; the load LD 1 、LD 2 The capacity is 8+j0.5MVA, 2MVA; fault point f 1 , f 2 respectively located in IBDG 2 , IBDG 3 between and the ends of the busbar MN.

[0060] An adaptive longitudinal protection method for distributed power distribution networks with inverters, such as figure 2 shown, including the following steps:

[0061] (1) Power on the relay protection device;

[0062] (2) Initialize line parameters;

[0063] The initialization line parameters include: initializing the rated current of the distributed power supply within the protection range Initialize the line impedance Z between distributed power sources 0 ,Z 1 ,…Z i ,…Z n , where Z 0 is...

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Abstract

The invention belongs to the field of relay protection of electric power systems, and relates to an adaptive longitudinal protection method for distribution networks with inverter-type distributed power sources, comprising the following steps: initializing line parameters; adjusting the installed capacity of each distributed power source; obtaining faults Voltage vector and current vector before and after; set the action threshold ΔI' of fault component current differential protection IBDG_thre and braking coefficient k' res ; Calculate the positive sequence voltage of each PCC before the fault; calculate the sum of the output power of the distributed power supply; calculate the reference active power of the distributed power supply; calculate the fault component positive sequence voltage of each PCC, and obtain the fault component output current of the distributed power supply ; Calculate the fault component differential current ΔI' of the line d and braking current ΔI' r ; Judgment ΔI' d Whether it is greater than k' at the same time res ΔI' r and ΔI' IBDG_thre , if it is, it is judged as an internal fault, and the protection action is initiated; otherwise, it indicates that there is no internal fault. The invention is not affected by line fault type, transition resistance, distributed power access capacity, access location, etc., and has strong applicability and high reliability.

Description

technical field [0001] The invention belongs to the field of relay protection of electric power systems, and relates to an adaptive longitudinal protection method for a distributed power distribution network including an inverter type. Background technique [0002] In order to alleviate the energy crisis and reduce environmental pollution, distributed power generation technology based on renewable energy such as solar energy and wind energy has been rapidly developed and widely used. The penetration rate of distributed power, especially inverter distributed power in the power grid is getting higher and higher. However, the access of inverter-type distributed power has changed the structure of the traditional distribution network, making it transform from a single-power radial network to a multi-source network. Not only that, the output of inverter distributed power depends on its control strategy, its fault response speed is very fast, and its transient process can be ignor...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/28H02H7/22H02J3/38
CPCH02H7/22H02H7/28
Inventor 李海锋邓成江许灿雄王钢
Owner SOUTH CHINA UNIV OF TECH
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