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A Method for Automatic Tracking and Adjustment of Harmonic Elimination Resistor

It is a technology of harmonic elimination resistance and automatic tracking. It is applied in circuits, electrical components, and electrical component structure associations. It can solve single-phase grounding, power frequency resonance protection dead zone, inability to distinguish single-phase grounding and power frequency resonance, and voltage mutual inductance. It can eliminate the problems of overload and burnout of the voltage transformer, and achieve the effect of eliminating the burning of the voltage transformer, eliminating the protection dead zone, eliminating the resonance and resonance overvoltage.

Active Publication Date: 2017-11-24
张安斌
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main defects of this method are as follows: firstly, when the single-phase grounding is applied for a long time, the resonance elimination resistor will cause the voltage transformer to be seriously overloaded and burned; secondly, it is impossible to distinguish between single-phase grounding and power frequency resonance; Judging whether it is frequency division, high frequency or power frequency resonance, if it is frequency division and high frequency resonance, put in the resonance elimination resistor, if it is power frequency resonance or single-phase grounding, after a short period of time, put in the resonance elimination resistor, no more resonance elimination , is a passive resonance elimination; fourth, the resonance elimination resistor consumes the energy generated by the resonance of the voltage transformer after resonance, which is a temporary solution but not the root cause; fifth, the system needs to withstand resonance overvoltage; sixth, there is a single-phase grounding, power frequency resonance protection dead zone
[0004] Obviously, the biggest defect of the microcomputer resonance eliminator is that it can implement the resonance elimination measures only after the voltage transformer resonates, and it is impossible to judge how much resonance elimination resistance to invest so that each winding is not overloaded.

Method used

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  • A Method for Automatic Tracking and Adjustment of Harmonic Elimination Resistor
  • A Method for Automatic Tracking and Adjustment of Harmonic Elimination Resistor
  • A Method for Automatic Tracking and Adjustment of Harmonic Elimination Resistor

Examples

Experimental program
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Effect test

Embodiment 1

[0066] It is known that K=1.9, S=50VA, the maximum operating voltage of the system is less than 1.1 times the rated voltage, and the long-term operation is at the open triangle voltage U △ =5V, at T1 time U △ mutation to U △ =80V, at T2 time U △ back to U △=100V, at T3 time U △ back to U △ =5V, automatically track the open triangle voltage to adjust the harmonic elimination resistor with the method of the present invention.

[0067] Since the maximum operating voltage of the system is less than 1.1 times the rated voltage, that is, λ 2 =1.1, and take λ 1 =1.1, according to formula (6), in U △ = Harmonic elimination resistor R at 5V X =2.02 ohms, take R 5 = 2.5 ohms; U △ = Harmonic elimination resistor R at 80V X = 55.57 ohms ohms, take R 80 = 56 ohms; U △ = Harmonic elimination resistor R at 100V X =77.19 ohms, take R 100 = 78 ohms.

[0068] First in the system long run in U △ When =5V, the resistance across the open triangle is R X = R 5 = 2.5 ohms; U is me...

Embodiment 2

[0070] It is known that K=2.5 and S=50VA. Since it is a terminal substation and a remote pump station substation with long line power supply and load instability, the capacitance effect of the system is very serious. When there is no load, the voltage is very high, so the system runs The maximum voltage is less than 1.2 times the rated voltage, long-term operation at the open triangle voltage U △ =0V, at T1 time U △ mutation to U △ =70V, at T2 time U △ back to U △ =100V, at T3 time U △ back to U △ = 0V, automatically track the open triangle voltage to adjust the harmonic elimination resistor with the method of the present invention.

[0071] Since the maximum operating voltage of the system is less than 1.2 times the rated voltage, λ is taken as 2 =1.2, according to formula (7), in U △ = Harmonic elimination resistor R at 0V X =0 ohm, when the open triangle can no longer be monitored by shorting the open triangle, take R 0 = 1 ohm; U △ = Harmonic elimination resistor...

Embodiment 3

[0074] It is known that K=1.9, S=50VA, the maximum operating voltage of the system is less than 1.1 times the rated voltage, and the long-term operation is at the open triangle voltage U △ =5V, at T1 time U △ mutation to U △ =80V, at T2 time U △ back to U △ =100V, at T3 time U △ back to U △ = 60V, at T4 time U △ back to U △ =5V system returns to normal.

[0075] The maximum operating voltage of the system is less than 1.1 times the rated voltage, that is, λ 2 = 1.1, λ 1 =1.1, according to the open triangle voltage is divided into 6 sections N=6, according to formula (9) to obtain R i , corresponding to parameter U Δi , I i See Table 1.

[0076]

[0077] Long run under U △ =5V, the harmonic elimination resistor works in the first section, the harmonic elimination resistor R X = R 1 = 8 ohms. U is detected at time T1 △ mutation to U △ =80V>U Δ1+ =10V, adjust the harmonic elimination resistor to U △ = 80V corresponding to the fifth segment resistance R X =...

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Abstract

The invention discloses a method for automatically tracking and adjusting the harmonic elimination resistance, which is characterized in that: the harmonic elimination resistance RX is connected across the two ends of the open triangle of the voltage transformer, and the open triangle current I is: I=U△ / RX, the winding M is the phase winding with the highest voltage among the three windings of the open triangle. When the operating power UMI of the winding M is not greater than the limit power KS of the winding M, set the harmonic elimination resistor RX to track the open triangle voltage U△ for adjustment. The method of the invention realizes active resonance elimination, actively consumes the energy that causes resonance, fundamentally completely eradicates the resonance of the voltage transformer and its overvoltage, does not have a protection dead zone, and ensures the safe operation of the system.

Description

technical field [0001] The invention relates to a method for automatically tracking and adjusting the harmonic elimination resistance of a voltage transformer. Background technique [0002] Potential transformer resonance is a very common power failure and accident, especially in distribution network. On the one hand, there are many ferromagnetic resonance overvoltages caused by the saturation of voltage transformer iron cores. Although some measures to limit resonance overvoltages have been taken, such as resonance elimination Lamps, harmonic eliminators, TV high-voltage neutral points add resistors or a single TV, etc., but the problem has not been fundamentally solved. TV burning and fuse blowing still occur continuously; on the other hand, since the main characteristic of the neutral point ungrounded operation mode is that after single-phase grounding, it is allowed to maintain for a certain period of time so as not to cause power outages for users, generally 2 hours. W...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F27/34H01F27/40
CPCH01F27/343H01F27/40H01F27/402
Inventor 张安斌
Owner 张安斌
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