Generator earthing and stator earth fault protection
LIOU designed and manufactured a Medium-Voltage resin cast type CBCT current transformer for generator earthing and stator earth fault protection.
Description:
The stator grounding fault, which is caused by the insulation damage between stator winding and iron core, is very common to the large generator. Since the large generator has larger shunt capacitance to earth, the fault current may exceed the capacity of the generator. In order to sensitively respond to grounding fault of stator winding, the 100% stator ground fault protection must be equipped for all generators with capacity of no less than 100MW.To this end, there are three types of stator grounding protection at present,which are the fundamental zero sequence voltage based stator grounding protection, the third harmonic voltage based stator grounding protection, and the injection-based stator grounding protection.
Net Weight:250KG Size:1030*220*455mm Window size:800*140mm
Installation On Site
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– rectangular shaped core balance current transformer – 100/1 [A/A] – 15 [VA] – 5P20 – Dimension of the window [mm] – suitable for the busbars as shown in the below pictures – Standard IEC 61869 standard and more |
The CBCT will work for a generator earth-fault protection. The generator has delta connected stator. Generator parameters:
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CB compartment (on left side) |
Busbar compartment (on right side) | ||
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Dimensions of yellow-marked space - Planning to install rectangle shaped CBCT in yellow marked space. |
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220mm (between two isolators) |
120mm (from isolator to busbar connection) 240mm (from isolator to busbar edge) |
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740mm (between 3 busbars) |
425mm (from support to floor) |
180mm (from busbar to below support) |
140mm (from busbar to support) |
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Technical Requirements
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S/N |
Descriptions |
Unit |
Specs |
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1 |
Highest voltage for equipment |
[kV] |
10KV |
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2 |
Power capacity |
[VA] |
15VA |
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3 |
Rated power-frequency withstand voltage |
[kV] |
42KV |
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4 |
Rated lightning impulse withstand voltage |
[kV] |
75KV |
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5 |
Rated frequency |
[f] |
50-60HZ |
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6 |
Rated primary current |
[A] |
100A |
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7 |
Rated secondary current |
[A] |
1A |
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8 |
Rated short-time thermal current |
[A] |
20KA/s |
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9 |
Rated dynamic current |
[A] |
50KA |
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10 |
Conformity with standard and accuracy classes |
5P20 |
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11 |
Operating temperature range |
[℃] |
-20℃-125℃ |
