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Transient control method of vdcol for series mtdc system and its vdcol synthesizer

A control method, series-type technology, applied to emergency protection circuit devices for limiting overcurrent/overvoltage, power transmission AC networks, circuit devices, etc. problem, to achieve the effect of improving stability

Active Publication Date: 2016-11-09
HITACHI ENERGY SWITZERLAND AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0021] However, during DC voltage sags, the relationship in (2) is no longer satisfied and can cause the system to build up to an abnormal operating point

Method used

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  • Transient control method of vdcol for series mtdc system and its vdcol synthesizer
  • Transient control method of vdcol for series mtdc system and its vdcol synthesizer
  • Transient control method of vdcol for series mtdc system and its vdcol synthesizer

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Embodiment Construction

[0049] Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. In the interest of clarity and conciseness, not all features of an actual implementation are described in the specification.

[0050] Figure 5 A flowchart showing a VDCOL control method for a series-type MTDC system according to an embodiment of the present invention.

[0051] Such as Figure 5 As shown, a low voltage current limiting cell (VDCOL) method 500 for a series MTDC system includes the following steps:

[0052] Step 502, select a converter station as a current setting terminal and enable its VDCOL. Every converter station has VDCOL function, but only CST has VDCOL function enabled and VST will receive current reference from CST. The enabled VDCOL receives the current command from the main controller and obtains the measured DC voltage value across each converter station as input for each VDCOL sub-module.

[0053] Step 504, calculate the cu...

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Abstract

A VDCOL (Voltage Dependent Current Order Limiter) control method for a series MTDC (Multi-Terminal HVDC) system comprises calculating the current order limitation value of each converter by respective VDCOL submodule, comparing all the current order limitation values of each converter, and choosing the minimal current order limitation value as a common current order. Meanwhile a synthesizer thereof is provided. The solutions of the method and synthesizer are to protect the series MTDC system during faults and also improve the AC system stability.

Description

technical field [0001] The present invention relates to the technical field of series MTDC (multi-terminal HVDC) systems, and more particularly, to a VDCOL (low voltage current limiter) control method and a VDCOL synthesizer for series MTDC systems. Background technique [0002] VDCOL is commonly used in HVDC systems to reduce the DC current when the DC voltage drops significantly. Use VDCOL for the following reasons: [0003] 1. Avoid power instability during and after disturbances in AC networks; [0004] 2. Define a fast and controlled restart after AC and DC faults are cleared; [0005] 3. To avoid current stress on the thyristors during successive commutation failures; and [0006] 4. Reduce the probability of continuous commutation failure when the AC voltage is restored. [0007] In HVDC systems, the DC voltage is measured to generate a current limit command corresponding to a predefined V / I characteristic curve. [0008] figure 1 Typical VDCOL characteristics f...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/36H02H9/02
CPCH02J3/36H02J2003/365Y02E60/60
Inventor 杨晓波姚大伟苑春明岳程燕
Owner HITACHI ENERGY SWITZERLAND AG