Method and system of stator grounding protection method and system connected in series with resistance from arc suppression coil
A technology for stator grounding protection and arc suppression coil, which is applied to emergency protection circuit devices, emergency protection circuit devices, electrical components and other directions for limiting overcurrent/overvoltage, which can solve the problem of low inductance and low inductance value of arc suppression coils. , to protect the application effect is not ideal and other problems, to achieve the effect of easy implementation, increase in size, and improve signal measurement conditions
Active Publication Date: 2022-06-28
TIANSHENGQIAO TWO HYDROPOWER CO LTD +1
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Problems solved by technology
In order to compensate the capacitive current, the inductance value of the arc suppressing coil is small, resulting in a small inductive reactance at 20Hz, resulting in a small 20Hz signal injected from the power supply unit to the neutral point of the generator when the injection stator grounding protection is applied. The measurement of the signal brings difficulties, which ultimately leads to unsatisfactory protection application effect
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Embodiment Construction
[0033] The present embodiment will be clearly described below with reference to the accompanying drawings.
[0034] In this embodiment, a resistance injection type stator grounding protection method is connected in series from the arc suppression coil. The arc coil 1 is connected in series with the resistor 3 (used to suppress the transmission of overvoltage) to realize the injection of the 20Hz signal of the injected stator grounding protection. The method specifically includes the following steps:
[0035] Step 1: Inject a 20Hz voltage signal from both ends of the arc suppression coil 1 connected in series with the resistor 3 on the neutral point side of the generator; the resistor divider of the stator grounding protection device 4 is connected to both ends of the resistor 3, and is detected by the resistor divider Injected voltage signal (see image 3 ); winding the intermediate current transformer 7 on the power output line, the intermediate current transformer 7 is con...
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The invention discloses a stator grounding protection method and system of the injection type stator grounding protection method and system from the arc suppression coil series connection resistance, comprising: injecting a 20 Hz voltage signal from both ends of the arc suppression coil series connection resistance on the neutral point side of the generator; the stator grounding protection device uses The measured 20Hz voltage and 20Hz current are calculated by impedance compensation to obtain the 20Hz voltage and 20Hz current actually injected into the two ends of the ground branch of the generator stator winding, and calculate the ground admittance, taking the reciprocal of the real part of the ground admittance, Then multiply the resistance conversion coefficient to get the ground fault transition resistance value; use the calculated ground fault transition resistance value as the protection criterion, when the calculated ground fault transition resistance value is lower than the high-level fixed value, the alarm action will be executed. When the calculated ground fault transition resistance value is lower than the low-level setting value, the tripping action is performed. The invention does not change the neutral point grounding mode of the generator, and can accurately calculate the grounding fault transition resistance value.
Description
technical field [0001] The invention belongs to the technical field of design and manufacture of large-scale hydro-generators and the relay protection of main equipment of power systems, and particularly relates to a method and system for grounding protection of stators connected in series with resistors from arc suppression coils. Background technique [0002] The stator single-phase ground fault is the most common fault of large generator stator winding insulation damage. The damage to the generator is mainly manifested in the burn of the stator core and the expansion of the ground fault into phase-to-phase or inter-turn short circuit. Therefore, the generator protects the A screen / B screen. It has become a trend to configure stator grounding protection with different principles (dual frequency and injection). [0003] The injection-type stator grounding protection has been widely used in the high-resistance grounding method of the generator neutral point through distribut...
Claims
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IPC IPC(8): H02H7/06H02H9/08
CPCH02H7/06H02H9/08
Inventor 钟波李刚周万竣周红斌叶锐黄凯徐子林王园园
Owner TIANSHENGQIAO TWO HYDROPOWER CO LTD