Yhptq thermistor current limiting harmonic eliminato

 
 
Yhptq thermistor current limiting harmonic eliminator
 
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product
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Anhui Yahui Electric Automation Co
, Ltd
1、 Product overview
  In the neutral point non effective grounding system, in order to measure the three phase to ground voltage and monitor the insulation to the ground, the neutral point of Pt is directly grounded
Because the load on the low-voltage side of Pt is very small and close to the no-load state, the equivalent excitation reactance seen from the high-voltage side to the ground is very large
After some switching operations or ground faults disappear, The equivalent excitation reactance of Pt will form a special resonance circuit with the equivalent capacitance of the system to the ground, which will excite various harmonic ferromagnetic resonance overvoltage and cause Pt saturation
Because the PT fuse can not effectively fuse the saturated excitation current of hundreds to thousands of Ma, it will eventually lead to PT burning loss, explosion of Pt cabinet and lightning arrester, bus short circuit, impact on the main transformer, threat to the personal * * of workers and other accidents, It poses a great threat to the operation of power grid and seriously affects the reliability of power supply

The traditional primary harmonic elimination damping resistor adopts varistor (usually silicon carbide material), that is, it presents high resistance under normal operation conditions
When resonance occurs, the resistance decreases, which is not conducive to eliminating resonance
Under normal operation, it will also affect the measurement accuracy of the transformer
In serious cases, it may amplify the unbalanced voltage at the neutral point, resulting in the failure of normal operation of the system; The secondary harmonic elimination has a poor effect on eliminating the resonance generated again, and will also have an impact on the measurement of the transformer

Yhptq thermistor current limiting harmonic eliminator developed by our company can realize continuous and rapid harmonic eliminator
The harmonic eliminator time of fundamental resonance is about 1
56s and that of frequency division resonance is about 2
1S
Under 3
5 times overvoltage, the current limiting harmonic eliminator can limit the PT excitation current below 100mA

2、 Working principle
  The damping effect of resistance can destroy the resonance condition and eliminate the resonance
Yhptq thermistor current limiting harmonic eliminator is installed in series between Pt neutral point and ground, and the resistance is 3K & Omega under normal operation; The impedance of Pt primary winding is megaohm, so it will not affect the performance of Pt, and will not significantly change the parameters of the system
When Pt resonates, the iron core is saturated, the excitation current of primary winding increases, the temperature of yhptq thermistor current limiting harmonic eliminator increases, and the resistance increases rapidly, which can play a better role in damping
Moreover, the greater the resonance energy, the shorter the yhptq thermistor current limiting harmonic eliminator, which is more beneficial to the insulation of the equipment

3、 Model designation and parameters

model naming	system rated voltage	better current
YHPTQ-6	6KV	200mA
YHPTQ-10	10KV
YHPTQ-35	35KV

IV
product features
  Yhptq thermistor current limiting harmonic eliminator has the advantages of simple structure, small volume, convenient installation and reliable operation;
  Under normal operating conditions, yhptq thermistor current limiting harmonic eliminator presents low resistance, does not change the operating conditions of voltage transformer, and will not affect the measurement accuracy of transformer
When Pt ferromagnetic resonance occurs, the primary current limiting harmonic eliminator realizes rapid harmonic elimination due to its fast high resistance;
  It can realize continuous and rapid harmonic elimination
The greater the amplitude of resonant overvoltage, the shorter the harmonic elimination time;
  It can limit the sudden increase of excitation current of primary winding of voltage transformer and prevent the bus short-circuit accident caused by the increase of primary winding current of voltage transformer and the failure of arc extinguishing due to insufficient energy after fuse fusing

5、 Overall dimension
 
 
 
 
Product outline drawing , Installation dimension drawing
 
 
This instruction manual is subject to change without notice

 
Anhui Yahui Electric Automation Co
, Ltd

Address: Liheng Industrial Park, West gongtou, bustling Avenue, Hefei
Tel: 0551-63889111 sixty-four million six hundred and sixty-nine thousand five hundred and seventy-one
Fax: 0551-63498768
Website: www
hfyahui
com com