James E. Bowen

Modeling of the pressure wave associated with arc fault

The development of computerized three-dimensional modeling for electrical arc events is presented. Data from a mathematical simulation of the pressure wave associated with arc faults are compared to experimental data obtained in equipment testing. Consequences of electrical arc faults and mitigation strategies are reviewed.

Improving safety and reliability via cost effective upgrades of existing systems

Recent focus has been placed on improving the reliability and safety of new equipment. This paper describes a few cost-effective upgrades and retrofits for existing electrical systems, which can improve maintenance effectiveness, reduce process downtime, limit physical exposure to hazards, and improve personnel safety. A typical power system, which comprises a high-voltage substation, medium-voltage switchgear, and low-voltage switchgear, has many attributes that are prone to failure and misoperation. These common features in existing systems can be unsafe since failures and misoperations typically result in increased exposure to hazards. A few select cost-effective upgrades or modifications that increase reliability and safety are presented in the general categories of protection, control, operation, and diagnostics

The effects of system grounding, bus insulation and probabilty on arc flash hazard reduction - The missing links

This paper provides a discussion on the theory behind reducing the risk and severity of an arc flash incident. In particular, the variables associated with the calculations of energies from an arcing fault are presented in an effort to show the futility of present methods for the determination of incident energy levels in the electrical industry. A number of commonly ignored design concepts that significantly reduces the risk of electrical hazards will be discussed two of which include 1) the system grounding and, 2) solid insulation. This paper will discuss risk and the management of risk as a means of reducing the probability of an incident. It will then show how risk-reduction should be used in the design, construction, operation and maintenance of electrical equipment as means for the safeguarding of employees in the workplace.

Is selectivity achieved in critical low-voltage UPS and standby generator power circuits?

This paper reviews typical critical low-voltage UPS (uninterruptible power supply) systems and standby generator power circuits used in the petrochemical industry to determine if selectivity is achieved between protective devices during short-circuit conditions. Alternate system configurations are proposed when selectivity is not achieved. Generator excitation systems and UPS support during fault conditions is discussed.

The Effects of System Grounding, Bus Insulation, and Probability On Arc Flash Hazard Reduction—Part 2: Testing

This paper provides a follow-up to the paper The Effects of System Grounding, Bus Insulation and Probability on Arc Flash Hazard Reduction-The Missing Links. In that paper, system grounding and bus insulation were considered a means of reducing the probability of an arc flash incident by approximately two orders of magnitude. In September 2013, additional testing was conducted on a low-voltage motor control center (LVMCC) with the expectation that engineering enhancements such as insulated vertical bus, high resistance grounding, and other techniques could be implemented to further reduce the probability of an arc flash incident. The testing performed was with faults initiated in locations typically found in operating petrochemical facilities, in LVMCCs, with the starter unit door open. This paper discusses the findings of testing on real-world electrical equipment in an effort to further understand and minimize the probability of an arc flash incident. This paper reviews the physics of the arcing fault and how ignition wire, geometry, and the number of anode/cathode pairs all contribute to arcing fault energy and personnel exposure.

CT saturation calculations - are they applicable in the modern world? - Part III, low-ratio, high-current CT/microprocessor relay comparisons at a high-current testing laboratory

Part III is an extension of the Part II testing effort, but with relay manufacturers providing, commissioning, and configuring the relays for the high-current test laboratory activities. Part III provides high-current testing laboratory results for multiple 50 kA and 63 kA tests involving several typical low-ratio switchgear CTpsilas (with typical burdens) and microprocessor feeder relay instantaneous 50 elements. Saturated low-ratio CT graphical waveform plots obtained from a series of tests are analyzed. Microprocessor relay 50 element true rms and bipolar peak detector relay filter algorithm types are considered. Discussions also include power system concerns resulting from delayed microprocessor relay instantaneous 50 element operation, i.e., arc flash PPE recommendations, relay coordination selectivity, equipment. Comments about electro-mechanical instantaneous relays are included.