Laboratory Studies of a New Stator Slot Wedge Tester for HV Generators

• Published in: IEEE transactions on energy conversion Vol. 24; no. 1; pp. 146 - 152
• Main Authors: Xiang Peng, Xiang Peng, Zhidong Jia, Zhidong Jia, Shengqiang Gao, Shengqiang Gao, Liming Wang, Liming Wang, Zhicheng Guan, Zhicheng Guan, Jie Yang, Jie Yang, Tianzheng Wang, Tianzheng Wang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2009; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acceleration; Bars; Devices; Digital signal processing; Digital signal processor (DSP); Digital signal processors; Embedded software; Generators; ground wall insulation; Hardware; high-voltage (HV) generators; Insulation; Laboratories; Mathematical models; slot wedge; Software design; Software testing; stator bar; Stator bars; Stator windings; Stators; tightness testing; Vibration; Wedges; winding vibration
• ISSN: 0885-8969; 1558-0059
• DOI: 10.1109/TEC.2008.2008881

Stator winding vibration is the most common cause of unexpected failure of high-voltage (HV) generators. Stator bars are generally fixed in slots by using slot wedges and a side packing system. Loose slot wedges could result in excessive vibration of the stator bars, which would accelerate the deterioration of the ground wall insulation. Loose slot wedge testing is consequently one of the most important general examination procedures to make sure the condition of HV generators. The common method used for slot wedge testing is manual measurement, whereby the slot wedge is tapped by hand using a small hammer. A judgment on looseness is made based on the sound from it. A digital signal processor (DSP)-based loose slot wedge tester is described in detail in this paper, including both hardware and software design. It was developed in our laboratory based on the study of slot wedge vibration characteristics in its loosening process. Since embedded software system of the DSP is oriented to a specific industrial field while PC system is of a general purpose, the device has many advantages compared to traditional manual measurement or other slot wedge testing equipment, such as portability, high intelligence, low power consumption, etc. The tester was applied for laboratory loose slot wedge testing of a slot model. The test results soundly verified the good performance of the device.