Power Research

R. Panneer Selvam ¹, Yamini Gupta ¹

Affiliations
1 Central Power Research Institute, Bengaluru – 560080, Karnataka, IN

Abstract

Dynamic seismic force causes damage to electrical equipment and structures resulting in loss of human and animal life. High voltage substation equipment are highly vulnerable to earthquake event compared to low voltage distribution network. Vulnerability to seismic event increases with increase in voltage rating of substation due to taller and slender porcelain structures. Porcelain insulators used in substation equipment have high compressive strength but weak tensile strength. Hence ceramic insulators are the weakest part in the substation equipment in the event of earthquake. Earthquake with 0.1g zero period acceleration can cause massive damage to high voltage substation equipment. Substation equipment with composite insulator are comparatively less vulnerable to seismic loading. Central Power Research Institute (CPRI) is equipped with state-of-the-art tri-axial shake table facility for simulating tri-axial earthquake vibration. Seismic qualification methods, codal provisions and seismic performance of 145 kV three pole operated composite insulator SF6 circuit breaker by shake table method are discussed in this paper. The seismic strain at critical locations, response acceleration on circuit breaker are presented along with relative displacement at the terminal of circuit breaker.

Keywords

Damping, Natural Frequency, Seismic Qualification, Substation Equipment, 145kV SF6 Circuit Breaker

Full Text

     

R. Panneer Selvam ¹, A. N. N. Nampoothiri ¹, Yamini Gupta ¹, D. Nagesh Babu ¹

Affiliations
1 Central Power Research Institute, Bangalore – 560 080, Karnataka, IN

Abstract

Relays are the protection and switching devices in most of the control processes or equipment. Relays respond to one or more electrical quantities like voltage or current such that they open or close the contacts or circuits. Relays are subjected to vibration and mechanical shock due to operating environment, transportation, mishandling and earthquake. Operating environmental vibration and shock may result in spurious operation of relays. Understanding cause and effect of vibration on relay performance is paramount to ensure reliable functioning of relays. Relays should be designed for the anticipated operating environmental vibration and shock levels. Vibration and shock qualification is performed to determine if a product can withstand the rigors of its intended use environment, to insure the final design will not fall apart during shipping, for environmental stress screening and to weed out production defects. CPRI is equipped with state-of-the-art facilities to qualify equipment and components for vibration and shock conditions. Performance of relay under vibration environment is discussed in this paper.

Keywords

Resonance Frequency, Shock, Vibration.

Full Text

     

R. Panneer Selvam ¹, Yamini Gupta ¹

Affiliations
1 Central Power Research Institute, Bengaluru – 560080, Karnataka, IN

Abstract

Nuclear power plants are critical facility with safety being major concern. Equipment installed in nuclear power plant should have absolute reliability and guaranteed operation under extreme environmental conditions. Earthquake is one of the devastating natural environmental condition. Nuclear power plant equipment and structures should perform its safety related function during and/or after an earthquake. Motor control centres, Distribution boards, Power cum motor control centres, LT panels are part of safety related equipment in nuclear power plant, normal functioning of these panels during and/or after earthquake is highly essential for safe power plant operation. Designing of equipment for seismic dynamic loading and validating design by shake table testing will ensure safe functioning of nuclear power plant in the event of earthquake. Based on geographical location of nuclear power plant seismic loading details are estimated, site specific and floor specific earthquake loads are used for design. Central Power Research Institute (CPRI) is equipped with state-of-the-art tri-axial shake table facility for simulating true earthquake vibration. Seismic qualification methods, codal provisions and seismic qualification of Power cum Motor Control Centre (PMCC) Panel used in nuclear power plant by shake table method is discussed in this paper.

Keywords

Damping, Natural Frequency, Seismic Qualification, PMCC.

Full Text

     

R. Panneer Selvam ¹, Yamini Gupta ¹, D. Nagesh Babu ¹

Affiliations
1 Central Power Research Institute, Bengaluru – 560010, Karnataka, IN

Abstract

Switchgear and controlgear plays a vital role in electrical power distribution system. Switchgear and controlgear are designed for electrical performance requirements including short circuit, temperature and humidity environmental conditions. But design aspects due to a seismic event are usually not taken into consideration. Earthquake shock waves causes vigorous ground shaking which are three dimensional in nature. Past-earthquake records have revealed that electrical equipment are vulnerable to seismic event, this lead to an increased focus on the earthquake performance evaluation of electrical equipment. Dynamic loading due to earthquake should be considered at the design stage in addition to other performance parameters. Designing switchgear for earthquake loading and validating design by testing can ensure uninterrupted and safe power supply during crucial time of post-earthquake rescue operations. In case of metal enclosed switchgear, functioning of equipment during and after seismic event is the major concern. Malfunctioning due to breaking or loosening or deformation of components, loss of output due to open circuit or short circuit and spurious operation of protective relays are observed during past seismic events. Central Power Research Institute (CPRI) is equipped with stateof- the-art tri-axial shake table facility for simulating true earthquake vibration. Seismic performance evaluation of high voltage switchgear by shake table method is presented in this paper.

Keywords

Damping, H V Switchgear and Controlgear, Natural Frequency, Seismic Qualification.

Full Text

     

R. Panneer Selvam ¹, Yamini Gupta ², D. Nagesh Babu ³

Affiliations
1 Joint Director, Central Power Research Institute, Bengaluru – 560080, Karnataka, IN
2 Engineering Officer, Central Power Research Institute, Bengaluru – 560080, Karnataka, IN
3 Engineering Assistant, Central Power Research Institute, Bengaluru – 560080, Karnataka, IN

Abstract

Equipment is subjected to vibration due to operating environment, transportation, handling and earthquake. Vibration results in dynamic loading, wherein failure of equipment depends on magnitude and frequency content of vibration. Equipment should perform its desired function during and/or after the vibration. The need to understand the effects of vibration and shock on equipment reliability is paramount. Vibration qualification is performed to determine if a product can withstand the rigors of its intended use environment, to ensure the final design will not fall apart during shipping, for environmental stress screening to weed out production defects, or even as a form of accelerated stress testing. Vibration tests are commonly used to improve the reliability of instruments, sub components and equipment or a system. Earthquake is the natural disaster which results in three-dimensional ground vibrations. Failure analysis of electrical equipment subjected to operational vibration environment is presented in this paper.

Keywords

Damping, Resonance Frequency, Vibration

Full Text