6.3KV generator neutral point arc suppression coil 10.5KV generator arc suppression coil

series generator neutral point arc suppression coil grounding compensation device, introduction b:
, generator neutral point grounding scheme introduction b:
, introduction to the arc suppression coil grounding principle b:
, Implementation standards b:
, Technical parameters b:
, Selection and appearance b:
, Pre-sales and after-sales services b:
, Installation, operation and maintenance precautions b:
, Ordering Instructions b:
, Packaging, transportation and storage b:


Contact: Li Wei


R series generator neutral point arc suppression coil grounding compensation device
． Foreword

In the power system, whether the neutral point of the generator is grounded and how to operate it is a comprehensive issue involving many aspects such as technology, economy, and safety. Corresponding grounding methods are adopted according to different operating requirements. In order to ensure the safety of people and equipment, it is necessary to strengthen the research on the neutral point grounding method of electrical equipment in order to determine a grounding method that is both safe, reliable and beneficial to economical operation.
The neutral point grounding method of the generator directly affects the reliability of the power supply, the insulation level of the lines and equipment, and the function of the relay protection device. As the requirements for power grid operation indicators increase day by day, the correct choice of neutral point grounding method becomes even more important.
The neutral point of the generator adopts indirect grounding method. When a single-phase ground fault occurs in the generator stator winding, since it cannot form a short-circuit loop, the ground fault current is often much smaller than the load current, so this system is called a small ground current system. The current flowing through the ground point is the ground capacitance current of the components connected to the generator's lead loop (main busbar, factory branch line, main transformer low-voltage winding, etc.). When the allowable value is exceeded (see Table 1 for allowable values), the stator core will be burned, thereby damaging the stator winding insulation, causing short circuits between turns or phases. Therefore, it is necessary to take measures to ground the neutral point of the generator through arc suppression coils or high resistance grounding. , to protect the generator from damage.
Table
Allowable value of single-phase ground fault current of generator stator winding
Generator rated voltage () b:
Generator rated capacity b:
Allowable value of fault current
.b:
b:
.b:
Steam turbine generator b:
～b:
b:
Hydraulic power generation Machine b:
～b:
.～.b:
Steam turbine generator b:
～b:
b:
Hydraulic generator b:
～b:
～b:
～b:
*For hydrogen-cooled generators, the allowable ground current value is.


． Introduction to the generator neutral point grounding scheme

When choosing the generator neutral point grounding method, the damage to the insulation caused by overvoltage, the damage to the iron core caused by the stator single-phase grounding current, and the stator grounding protection must be considered. There are many issues such as configuration and outlet action mode, design and manufacturing of grounding devices, and system operation.
The neutral point of the generator mainly adopts three methods: ungrounding, grounding through arc suppression coil, resistance or direct grounding.
. Generator neutral point non-grounding method: When the generator is single-phase grounded, the grounding point only flows through the capacitor current of the other two phases of the system that are electrically connected to the generator. When this current is small, the fault point The arc can often be extinguished automatically, so the reliability of power supply can be greatly improved. When the neutral point is not grounded and the capacitor current is less than ampere, the single-phase grounding protection only needs to use the other sequence voltage on the open side of the three-phase five-column voltage transformer to give a signal. The main disadvantage of the ungrounded neutral point method is that the internal overvoltage is a high multiple of the phase voltage.
. The neutral point of the generator is grounded through the arc suppression coil: When the generator capacitor current is large, the neutral point is generally grounded through the arc suppression coil. This mainly considers that when the grounding current is large enough to a certain extent, the arc at the grounding point cannot Automatically extinguishes. Moreover, if the stator core is burned out by ground current, it will be difficult to repair. After the neutral point is connected to an arc suppression coil, an inductive current can be generated when a single phase is grounded, which compensates for the capacitive current at the grounding point and causes the arc at the grounding point to automatically extinguish.
. The neutral point of the generator is grounded through a resistor or directly: Although single-phase grounding is relatively simple in this method and the internal overvoltage is a low multiple of the phase voltage, the single-phase grounding short-circuit current is very large, even exceeding the three-phase Short-circuit current may damage the stator winding and iron core of the generator, and may cause short-circuit current waveform distortion when a fault occurs, complicating relay protection.