Multi-channel VSI fed large variable speed asynchronous hydro-condenser: fault analysis, fault diagnosis and fault tolerant control

• Published in: IET renewable power generation Vol. 13; no. 3; pp. 438 - 450
• Main Authors: Joseph, Anto, Chelliah, Thanga Raj, Lee, Kyo-Beum
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 25.02.2019
• Subjects: asynchronous machines; condenser operation; control circuit failures; control circuit faults; converters; DFIM unit; dynamic behaviour; failure analysis; fault analysis; fault diagnosis; fault tolerant control; fault tolerant operation; high dynamic stability; hydroelectric power stations; hydro‐generating unit; invertors; machine control; multichannel VSI; multilevel voltage source inverter; open switch fault; power 2.2 kW; power 250.0 MW; power converter redundancy operation; power flow diagram; power generation control; power generation faults; power generation reliability; power grids; power system dynamic stability; reactive power control; reactive power support; reduced power converter rating; Research Article; rotor side control; rotors; survivability status; variable speed asynchronous hydro‐condenser; variable speed HU; voltage‐source convertors; survivability status; machine control; fault diagnosis; power 250.0 MW; multilevel voltage source inverter; power converter redundancy operation; hydro-generating unit; power generation control; hydroelectric power stations; failure analysis; reactive power support; invertors; multichannel VSI; converters; power generation faults; fault tolerant operation; power grids; variable speed asynchronous hydro-condenser; rotor side control; rotors; power generation reliability; asynchronous machines; power flow diagram; control circuit failures; reduced power converter rating; fault analysis; control circuit faults; condenser operation; voltage-source convertors; power 2.2 kW; variable speed HU; dynamic behaviour; high dynamic stability; reactive power control; power system dynamic stability; DFIM unit; open switch fault; fault tolerant control
• ISSN: 1752-1416; 1752-1424; 1752-1424
• DOI: 10.1049/iet-rpg.2018.5280

Multi-level voltage source inverter (VSI) fed doubly fed induction machine (DFIM) has gained prominence in large rated hydro-generating unit (HU) since it provides part load operation with reduced power converter rating and high dynamic stability. Power converters connected in rotor side control real and reactive power of the unit. This study discusses the condenser operation of variable speed HU (250 MW), to be commissioned in Tehri plant (India), with the power flow diagram. Further, it provides dynamic behaviour and survivability status of the DFIM unit during power converter and control circuit faults where power converter redundancy is not available in large rated DFIM unit. Economic analysis of 250 MW HU under power converter and control circuit failures are also investigated. The present work also explores fault tolerant operation of a 250 MW DFIM unit at open switch fault in converters to increase the continuity of the unit operation which provides additional 2% of reactive power support to the grid compared to the DFIM without power converter redundancy operation. Open switch fault is detected through Park's vector phase currents technique and variation in DC link voltage. The computer simulation results are validated in an experiment carried on 2.2 kW DFIM in the laboratory.