Flashover characteristics of barrier insulation under uni-directional and bi-directional oscillatory impulse voltages

Cornick, K.J.; Couper, I.D.; Guan, Z.C.

doi:10.1109/icpadm.1988.38500

Cited by 1 publication

(3 citation statements)

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“…When the barrier is close to either of the electrodes the influence of barrier becomes small and breakdown voltage approaches a value close to the clean air gap. Under unidirectional oscillatory impulse voltages due to unipolar nature of impulse the charges injected in the gap gets deposited on the surface of the barrier and inhibits the applied electric field, thereby improves breakdown strength of the composite gap,whereas under bidirectional oscillatory impulse voltages the charges injected in the first cycle gets swamped in the next half cycle leaving remanent charges thereby charges of both polarities gets deposited on the surface of barrier and subsequent peaks of the sinebidirectional oscillatory impulse voltages influencesthe breakdown voltage [5]. * It is observed that the breakdown voltage of oscillatory impulse voltage and switching impulse voltages are less than that of standard lightning impulse voltages, irrespective of position of the barrier in the rod-barrier-rod gap configuration analysed in the present work.…”

Section: Resultsmentioning

confidence: 98%

“…Similar observations have been made by Comick et a1. [5] in long gaps with rod-rod configuration by keeping different types of barriers. The optimal increase in breakdown voltages of the gap is in the range of 5-10% under positive polarity in both unidirectional and voltages, the maximum increase in breakdown voltage of upto 50% is observed.…”

Section: Methodsmentioning

confidence: 99%

“…LiMing et a1., [4] studied the breakdown characteristics of rodbarrier-rod gap under the DC voltage. Cornick et a1., [5] studied the breakdown characteristics of rodbarrier-rod gap under oscillatory impulse voltages in the limited frequency range. The review of past research shows a lack of experimental data on the effect of barrier on the breakdown characteristics of rod-rod configuration under oscillatory impulse voltage especially in short air gap and hence a credible data base has to be generated.…”

Section: Introductionmentioning

confidence: 99%

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Effect of barrier in short air gaps under oscillatory impulse voltages

Sarathi

Karri²

IEEE 1997 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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In this paper, the results of investigation carried out to understand the influence of barrier in a short air gap with the Rod-Rod configuration under oscillatory impulse voltages (UOIV, SBOIV, CBOIV) of different frequencies and dampings are presented. For the purpose of comparison, results obtained under AC, DC, LI and SI voltages are also provided. IntroductionElectric or dielectric strength is an important concept for an insulation design engineer. With the advancement of power transmission capacity, it has become necessary to design a reliable, compact and cost effective insulation system. The major cause of failure of electrical insulation and subsequent damages and outages in electrical power systems are due to transient over voltages caused by lightning, switching operations, line faults, etc., cause a wide variety of non-standard wave-shapes which are oscillatory in nature. The generated Oscillatory Impulse Voltages (OIVs) are complex in nature, identified by their freYpency, decay rate etc. These oscillatory transient voltages are either unidirectional, cos-bidirectional or sine-bidirectional in nature. The frequency of oscillations produced by lightning is in the range of several hundred Hertz and that of produced by line faults or switching over voltages is in the order of 1 to 100 kHz [l].

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Section: Resultsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%