Island flexible DC output system fault crossing control method and system
A technology of system failure and control method, applied in the direction of reducing/preventing power oscillation, power transmission AC network, single-grid parallel feeding arrangement, etc. The effect of avoiding power shortage, reducing shock, and smooth control
Pending Publication Date: 2018-07-06
CHINA ELECTRIC POWER RES INST +2
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Problems solved by technology
Island grid-connected new energy units no longer have the support of synchronous power supply through AC integration, and are connected to the flexible DC power grid after DC conversion. Once the DC grid fails, it is difficult for thousands of new energy units to accurately and timely sense the occurrence of the fault and respond accordingly. Rapid control based on this may cause the power injected into the DC grid to exceed the limit, resulting in the collapse of the DC grid
[0003] Therefore, when the DC grid fails, it is necessary to study the power coordination control between the isolated island access power station and the DC grid. However, the power station can only use AC convergence because the cost of DC integration is too high. Feedback and enable power emergency control
Method used
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Embodiment Construction
[0060] In order to better understand the present invention, the content of the present invention will be further described below in conjunction with the accompanying drawings and examples.
[0061] The present invention provides a fault ride-through control method for the island soft direct sending system, such as figure 1 As shown, the details are as follows:
[0062] When the flexible DC converter station fails, the flexible DC converter station is put into braking resistor;
[0063] When the fault is cleared, the flexible DC converter station sends out a control signal, and the power station receives the control signal to start active power control;
[0064] When the active power value of the flexible DC converter station reaches the preset active power control target, the braking resistor is withdrawn according to the preset rules to complete the fault ride-through.
[0065] The specific application of the fault ride-through control method of the island soft direct sendi...
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The invention relates to an island flexible DC output system fault crossing control method and system. According to the method, when a flexible DC grid is in fault, a flexible DC converter station starts AC side energy consumption braking, and a braking resistor is switched in; after the fault is eliminated, the flexible DC converter station emits a control signal, the control signal is received by a power station to start a new energy active power control system; if an active power value is regulated by the active power control system to reach a pre-set active power control target value, thebrake resistor is gradually withdrawn to complete fault crossing. The method is advantaged in that when the DC grid is in fault, the braking resistor is timely switched into to consume power emitted by the new energy, power control of the new energy station is further started, after power control meets requirements, the braking resistor is gradually withdrawn, not only can smooth control be realized, but also fault crossing is realized.
Description
technical field [0001] The invention relates to the technical field of fault ride-through control of new energy sent by an isolated island connected to a flexible DC power grid, and proposes a fault ride-through control method and system for an isolated island flexible direct feed system. Background technique [0002] Large-scale new energy long-distance transmission has become the main way for new energy to be delivered and consumed. However, as the proportion of synchronous power supplies gradually decreases, or even stops development, how to transport new energy with weak or no synchronous support has become a research hotspot. Therefore, it will become a future trend to study flexible DC transmission technology and propose that the application of flexible DC transmission technology in power grids to solve large-scale wind power transmission. Island grid-connected new energy units no longer have the support of synchronous power supply through AC integration, and are conne...
Claims
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Patent Timeline
Login to View More IPC IPC(8): H02J3/38H02J3/36H02J3/48H02J3/24
CPCH02J3/24H02J3/36H02J3/38H02J2003/365H02J3/388Y02E60/60
Inventor 李琰刘超迟永宁
Owner CHINA ELECTRIC POWER RES INST