Overhaul

Contact us

Shandong Qingneng Power Co., Ltd.
Tel: +86-536-3289907/3290518
Fax: +86-536-3291618
E-mail: info@qnpower.com
ADD: No.3011 Haidai North Road,Qingzhou City, Shandong Province, China


OverhaulLocation : Home > Overhaul

Electrical Cabinet Care

I. High & Low voltage cabinets installation of power plant 
1. 10KV high voltage switch cabinet installation of power plant
2. 0.4KV low voltage switch cabinet installation of power plant
3. Installation of generator protection system, synchronization system, transformer protection, H.V. motor protection, circuit protection in a power plant.
II. Electrical configuration testing items of power plant 
1. Vacuum circuit breaker insulation resistance measurement, each phase circuit resistance measurement and AC voltage withstand tests of 10KV H.V. switch cabinet.
2. DC resistance measurement of CT and PT, polarity test, ratio test, AC voltage withstand tests in 10KV H.V. switch cabinet.
3. AC voltage withstand tests for whole 10KV H.V. switch cabinet.
4. AC resonant test for 10KV H.V. electric cable.
5. DC resistance measurement of generator stator and rotor.
6. Generator stator coil insulation resistance measurement and DC voltage withstand tests.
7. Generator rotor insulation resistance measurement.
8. Generator rotor AC impedance and power loss tests.
9. No-load characteristic test of generator
10. Generator checking phase sequence (fist checking phase and second checking phase separately).
11. Generator short circuit characteristic test.
12. Measurement of residual voltage of stator after automatic magnetic blow-out and switch opening of generator.
13. Generator shaft voltage measurement.
14. Generator simulate synchronization.
15. All of the second circuit checking, measuring, switch tripping & closing tests, protection fixed value setting, protecting the STG trip test and magnetic blow-out tripping test for steam turbine and generator.

20170321123006422.jpg

III.Electrical problem troubleshooting in power plant
Problem Description: a coal mine’s 35KV H.T. switchgear OC protection tripped suddenly in He’nan Province, it caused sudden power lost of mine fan and endanger miner safety. 
Auto-reclosing via switchgears’ automatic reclosing function, through analysis, the reason is a set of 3000KW generator failure. Specific reason is: When the turbo-generator was running normally, exciting voltage lost suddenly, leading phase operation happened, the generator absorbed reactive power and lead to becoming motor running. Generator protection and power plant connecting line protection did not launch. After the generator absorbed a certain value of reactive power, the 35KV H.T. switchgear’s OC protection tripped. 

Investigation: generator and power plant connecting line protection setting fixed value exceed the protection fixed value of 35KV switchgear side, it lead to nearby protection did not launch and override trip when generator failure.