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Concrete encapsulated electrodes have been in use for over 40 years, and in general have been found to be an effective and safe component in grounding systems of industrial and commercial power systems as well as in lightning protection systems. As a current conducting medium, concrete is a fair conductor, similar to many moist soils. Concrete's ability to quickly absorb moisture and release it slowly...
The following topics are dealt with: industrial power systems; commercial power systems; energy systems; power system protection; and power system engineering.
In a lighting system design to estimate the actual energy efficiency of lighting control systems is an important goal since an accurate evaluation could help and guide designers towards the most appropriate control system. This paper analyzes the methodology for calculating energy consumption for lighting systems and the impact of the Building Automation and Control Systems (BACS). It promotes a comprehensive...
Injuries and deaths resulting from cranes or other equipment contacting overhead power lines occur all too frequently despite regulations that are intended to prevent such accidents. Historical data are explored and major underlying causes of such accidents are identified. Regulatory safeguards are considered, together with proposals for improving safety by making overhead lines more conspicuous....
In electrical installations each working zone and each sources node present a kit of operating instructions as a logic gene. Previous papers have introduced a new approach and a language of a closed logic code for operational procedures. This paper deals with some comments on definitions and the syntax of the operational language. A same status of switching defines working zones or nodes by double...
To support transformer load management (TLM), a narrow-band power line carrier (PLC) based identifier has been designed and developed for the determination of customers served by each distribution transformer. The transmission characteristics of PLC signal over low voltage distribution lines is simulated by using the mathematical model of distribution transformers, line conductors and customer loadings...
Torque ripple generated in the commutation interval is one of the main drawbacks of Brushless DC (BLDC) motors. This paper presents an comprehensive analysis on the generated torque ripples of trapezoidal back-EMF due to phase commutation in the six switch, three-phase inverter brushless dc motor drives. Experimental results verify the amplitude of the torque ripple under 4 kinds of PWM pattern, respectively.
This paper proposes a multi-region short-term load forecasting methodology, taking into account the Heat Index, a human-perceived equivalent temperature, to improve the load forecasting accuracy in Taiwan Power Company's (Taipower's) system. With the distinct climate characteristics due to Taiwan's long and narrow topography, it is difficult to obtain satisfactory load forecasting results by treating...
Traditionally, most end-use residential consumers receive flat rate monthly electricity bills based on load profiling rate calculations. Those flat rates do not relate and reflect the true and time-varying costs of electricity supply during actual time of consumptions. Without acknowledging the cost differences, consumers do not have any incentive to adjust their load consumption patterns, and inefficiencies...
This paper describes the experiences when revising and updating a key IEEE Standard for Electrical Power System Device Function Numbers, Acronyms and Contact Designations. The paper cites the historical evolution of this Standard, dating back to 1928. The wide utilization of modern, multi-function, relays and many new functions made clear the need to update the 1996 verison of this standad. Also,...
The frequency and duration of the various types of transmission line outages has a significant impact on the operation and reliability of industrial and commercial power systems. Knowledge of the statistical characteristics of transmission line outages (e.g., types of faults: three phase, line to ground, etc.) directly affects the protection and coordination practices at these facilities. Reliability...
The electrical power system from the Mexican refineries consists of a 13.8 kV synchronization bus. This scheme has been gradually expanded and now faces saturation and it is not possible to interconnect new loads and generation modules. The scheme is limited by the short circuit current from the power supplies and face voltage regulation problems. In this paper the conceptual design for the modernization...
To minimize the pollution that ships generate at ports, major ports all over the world are facing the challenge of upgrading their shore power infrastructure in order to make the provisions for shore-to-ship power supply systems. This process of supplying shore power to ships while turning off their on-board generators during berthing is called cold ironing. At present, there are no industry standards...
During the last years, increasing effort has been spent to advance offshore wind power. So far, only small test fields have been realized and the electrification of offshore wind farms still remains a research topic. Currently, offshore wind farms are equipped with three-phase ac grids, some of them will be connected to the transmission grid via an HVDC-link. Consequently, a dc system encompassing...
Higher efficiency electric motors can lead to significant reductions in the energy consumption and also reduce the environmental impact. In order to promote a competitive motor market transformation, a new international standard, the IEC 60034-30 has been approved. This standard globally harmonizes motor energy-efficiency classes in general-purpose, line-fed, three-phase, squirrel-cage, induction...
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