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Actuation of 50 Hz protection definite value by current instruction

A technology of current command and protection setting value, which is applied to emergency protection circuit devices, electrical components, circuit devices, etc., and can solve problems such as easy misoperation and easy refusal

Active Publication Date: 2008-09-17
NR ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The shortcomings of the existing DC harmonic protection methods: generally speaking, the magnitude of the 50Hz component of the DC current during a fault is proportional to the current (power) delivered by the DC system
If the setting value is too small, when the DC system transmits large current (high power) without failure, it is easy to malfunction
If the setting value is too large, when the DC system transmits small current (low power) and there is a fault, it is easy to refuse to move

Method used

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  • Actuation of 50 Hz protection definite value by current instruction
  • Actuation of 50 Hz protection definite value by current instruction
  • Actuation of 50 Hz protection definite value by current instruction

Examples

Experimental program
Comparison scheme
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Embodiment Construction

[0034] For the binary fixed value method, read the current command value, calculate (2), (3) formula, use figure 2 Realize the block diagram, and get the fixed value of DC harmonic protection (50Hz principle).

[0035] For the linear fixed value method, read the current command value, calculate the formula (4), and use image 3 Realize the block diagram, and get the fixed value of DC harmonic protection (50Hz principle). image 3 Realization block diagram of current command switching linear fixed value method

[0036] In the figure, the linearizer completes the function of (4).

[0037] Read the sampled value and calculate the formula (1) to realize DC harmonic protection (50Hz principle).

[0038] Reference for setting value selection: Binary value setting method, the setting value of the current command is about 0.4-0.5 times the rated DC current, the setting value 1 Genan project is 0.07 times the rated DC current, and the setting value 2 Genan project is 0.05 times the...

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Abstract

The invention is concerned with the method that uses the current dictate switch to 50Hz protecting fixed value, the IDNE_50HZ is bigger than the fixed value in the formula (1), the IDNE_50HZ is the computing IDNE50Hz component; the selection of the fixed value is: the fixed value is equal to the fixed value 1 (2) if the ID_ORD is bigger than the current dictate value, the fixed value is equal to the fixed value 2 (3) if the ID_ORD is smaller than and equal to the current dictate value, protects action if satisfies the condition (1) and delays; selects the fixed value in the condition (1) according to the (2) and (3) execution; the ID_ORD is the direct circuit dictate value in the formula (2) and formula (3), the fixed value 1 is the high fixed value, the fixed value 2 is the low fixed value.

Description

1. Technical field [0001] The invention relates to a method for switching a 50Hz protection fixed value by using a current command in the protection of a high-voltage direct current transmission system, and a related relay protection device. 2. Background technology [0002] Due to its unique advantages, such as: long distance, high power, asynchronous networking, fast power adjustment, power flow controllability, transmission economy, etc., HVDC transmission is more and more widely used. The core of the HVDC transmission system is the HVDC control and protection system, which includes a control system and a protection system. [0003] The grounding fault of the AC system, or the loss of pulses of the converter valve, etc., will cause the DC current to generate large harmonic current components (the main components are 50Hz and 100Hz components). The magnitude of the harmonic current is related to the magnitude of the transmitted power at the time of the fault. DC harmonic...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26H02J1/00
Inventor 王俊生李海英卢宇
Owner NR ELECTRIC CO LTD