Optimization method of direct-current transmission control protection system during strong oscillation of alternating-current system

A DC transmission control and AC system technology, applied in AC network circuits, power transmission AC networks, reducing/preventing power oscillations, etc., can solve problems such as instability, collapse, and lack of DC systems in large power grids, and achieve improved stability, Avoid collapse and reduce the effect of secondary impact

Inactive Publication Date: 2021-01-01
ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER COMPANY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This makes the multi-infeed DC transmission system, when the AC system oscillates, lacks the control strategy support of the DC system, resulting in the untimely response of DC control and protection, which is likely to cause instability or collapse of the large power grid.

Method used

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  • Optimization method of direct-current transmission control protection system during strong oscillation of alternating-current system
  • Optimization method of direct-current transmission control protection system during strong oscillation of alternating-current system
  • Optimization method of direct-current transmission control protection system during strong oscillation of alternating-current system

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Embodiment 1

[0033] like figure 1 As shown, Embodiment 1 of the present disclosure provides an optimization method for a DC transmission control and protection system during strong oscillation of an AC system, including the following steps:

[0034] Identify the out-of-step oscillation center position and oscillation mode. When the oscillation center is at the AC network position on the inverter side, and it is an out-of-step oscillation with an oscillation frequency less than 10Hz, automatically extend the DC transmission commutation failure protection time setting (currently conventional DC Phase failure protection time is set to 2.6 seconds);

[0035] At the same time, control the set value of decoupling time of the AC system on the inverter side to be less than the extended commutation failure protection time set value to ensure that the AC system completes decoupling and isolates the oscillation source before DC blocking, and reduces the out-of-step oscillation period of the AC networ...

Embodiment 2

[0048] Embodiment 2 of the present disclosure provides an optimization system for a DC transmission control and protection system during strong oscillation of an AC system, including:

[0049] The data acquisition module is configured to: acquire the operation status data of the AC and DC power grid system;

[0050] The oscillation identification module is configured to: identify the AC oscillation center position and oscillation mode according to the obtained operating state data;

[0051] The optimization control module is configured to: when the oscillation center is at the position of the AC network on the inverter side, and the oscillation frequency is out-of-step oscillation with an oscillation frequency lower than the preset frequency, prolong the DC transmission commutation failure protection time setting value, and control the AC system on the inverter side The delisting time setting value is less than the extended commutation failure protection time setting value.

...

Embodiment 3

[0054] Embodiment 3 of the present disclosure provides a computer-readable storage medium on which a program is stored. When the program is executed by a processor, the optimization of the DC transmission control and protection system during strong oscillation of the AC system as described in Embodiment 1 of the present disclosure is realized. Steps in the method, the steps being:

[0055] Obtain the operating status data of the AC and DC grid system;

[0056] Identify the AC oscillation center position and oscillation mode based on the obtained operating state data;

[0057] When the oscillation center is at the position of the AC network on the inverter side, and the out-of-step oscillation with the oscillation frequency less than the preset frequency, extend the DC transmission phase commutation failure protection time setting value, and control the inverter side AC system unloading time setting value to be less than the extended time Commutation failure protection time se...

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Abstract

The invention discloses an optimization method of a direct-current transmission control protection system in a strong oscillation period of an alternating-current system. The method comprises the following steps: acquiring running state data of an alternating-current and direct-current power grid system; identifying an alternating current oscillation center position and an oscillation mode according to the obtained operation state data; when the oscillation center is located at the inversion side alternating current network position and is out-of-step oscillation with the oscillation frequencysmaller than the preset frequency, prolonging the direct current power transmission commutation failure protection time constant value, and controlling the inversion side alternating current system splitting time constant value to be smaller than the prolonged commutation failure protection time constant value. By identifying out-of-step oscillation of the direct-current power transmission receiving-end alternating-current network and automatically switching direct-current control protection logic, commutation failure protection is switched to a long-delay constant value, it is guaranteed that the commutation failure protection long-delay constant value is greater than a receiving-end alternating-current system splitting constant value, and it is guaranteed that before a receiving end alternating current network disconnects an isolation oscillation source, direct current locking is avoided, the secondary impact on a receiving-end power grid due to DC locking is avoided, and system stability is guaranteed.

Description

technical field [0001] The present disclosure relates to the technical field of power systems, in particular to an optimization method for a DC transmission control and protection system during a strong oscillation of an AC system. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. [0003] Most of the existing power grids are large power grid systems including AC and DC hybrids. After the system is disturbed, it is easy to cause AC system oscillation. According to the degree (frequency) of system oscillation, it can be divided into low-frequency oscillation, out-of-step oscillation, sub-synchronous oscillation and super synchronous oscillation. synchronous oscillation etc. The DC transmission system itself has certain oscillation damping control characteristics. When the oscillation frequency is greater than 10Hz, the DC transmission control syste...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/24H02J3/36
CPCH02J3/241H02J3/36H02J2003/365Y02E60/60
Inventor 李宽李娜刘萌赵斌超李玉敦张国辉王昕张婉婕杨超史方芳王永波孙萌萌李聪聪梁正堂
Owner ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER COMPANY
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