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Hybrid cascade type direct-current fault ride-through system based on fault current limiter and control method

A DC fault ride-through and fault current limiter technology, applied in the direction of emergency protection circuit devices, electrical components, circuit devices for limiting overcurrent/overvoltage, etc., can solve the LCC commutation failure fault, MMC single-pole grounding fault Insufficient traversing ability and other problems, to achieve the effect of simple control, good recovery process and strong economy

Active Publication Date: 2021-06-11
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of the above problems, the object of the present invention is to provide a hybrid cascaded DC fault ride-through method based on a fault current limiter to overcome the current hybrid cascaded DC receiving terminal LCC commutation failure fault and MMC single-pole ground fault ride-through capability Insufficient problem

Method used

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  • Hybrid cascade type direct-current fault ride-through system based on fault current limiter and control method
  • Hybrid cascade type direct-current fault ride-through system based on fault current limiter and control method
  • Hybrid cascade type direct-current fault ride-through system based on fault current limiter and control method

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Embodiment Construction

[0035] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

[0036] The hybrid cascaded DC fault ride-through system based on the fault current limiter of the present invention includes multiple fault current limiters and their controllers. Between the DC inlets of the low-end MMCs at the cascaded DC receiving end.

[0037] When a commutation failure occurs in the high-end LCC of the hybrid cascaded DC receiving end, the fault current limiter controller detects that the DC current of the MMC reaches the fault current limiter start-up criterion current I set When the current limiting resistor is switched on, the DC fault current is suppressed to avoid the blocking of the MMC valve group.

[0038] When a single-pole ground fault occurs in a hybrid cascaded DC receiving-end low-end MMC, the fault current limiter uses its own topology to block the normal MMC and the discharge circuit of the faulty...

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Abstract

The invention discloses a hybrid cascade type direct-current fault ride-through system based on a fault current limiter and a control method. The hybrid cascade type direct-current fault ride-through system is characterized in that: the fault current limiter is arranged between a hybrid cascade type direct current receiving end high-end LCC direct current outlet and a corresponding hybrid cascade type direct current receiving end low-end MMC direct current inlet; after an LCC has a commutation failure fault, a fault current limiter control system detects that MMC direct current reaches fault current limiter starting criterion current, a current limiting resistor is put in, the direct current fault current is suppressed, and an MMC valve group is prevented from being locked; and when a low-end MMC at the receiving end has a single-pole grounding fault, the fault current limiter blocks a discharge loop from the normal MMC and the fault MMC to a fault point by means of the topology of the fault current limiter, and the MMC valve group is protected. Through simple control, ride-through of a high-end LCC commutation failure fault of the receiving end is achieved, the recovery process is good, ride-through of the low-end MMC single-pole grounding fault of the receiving end can be achieved without any control receiving end, the fault current limiter does not adopt a full-control device, and meanwhile the development problem of a large-capacity direct-current circuit breaker is avoided.

Description

technical field [0001] The invention relates to the technical field of direct current transmission, in particular to a hybrid cascaded direct current fault ride-through system and a control method based on a fault current limiter. Background technique [0002] The hybrid cascaded HVDC transmission system adopts LCC at the sending end, high-end LCC and low-end half-bridge MMC parallel group (MMCB) in direct series at the receiving end, combines the respective advantages of LCC and MMC, and naturally has the ability to ride through DC line faults. In addition, The low-end MMCB at the receiving end can provide certain reactive power support for the high-end LCC and reduce the risk of commutation failure in the LCC. [0003] The thyristor valve group has ten times the over-current margin, but the fully-controlled device IGBT used by MMC is relatively fragile and can only withstand the over-current of twice the rated current. When a commutation failure occurs in the high-end LCC...

Claims

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Application Information

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IPC IPC(8): H02H7/26H02H9/02
CPCH02H7/268H02H9/02
Inventor 江琴王相飞李保宏刘天琪
Owner SICHUAN UNIV
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