• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.803-805
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• 1993

This paper describes the development of a digital multifunction controller for the protection, measurement and control of the high voltage customer switchboard. The magnitude of the fundamental component is estimated using a simple filter based on cross-correlation with a heptagonal wave. The characteristics of flexible relay functions such as adjustable pickup and time-dial settings, various time-magnitude curve and directional capability including measurement functions are presented. The controller implementation is carried out on two microprocessors for real time operation.

• Journal of the Korean Professional Engineers Association
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• v.19 no.2
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• pp.10-20
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• 1986

This paper describes a countermeasure of electric utilities and customer equipment in order to minimize an effect of sensitive electrical and electronic equipment on the voltage disturbances. After being studied, some schemes to solve were discovered. Firstly, in the electric utilities, the reduction of frequency and influence of voltage drop's time are not easy to realize because of the standpoint of effect and economy. Secondly, in the customer equipment, there are some equipment to minimize the voltage disturbances, Such as an UPSs, a noise suppressors and a power conditioners. One of them should be established on the computer control and automated systems, the electromagnetic switch of delay-release type should be adopted on the electromagnetic switch, the controlling circuit should be adopted on the variable speed motors which is being considered a countermeasure for a momentary under-voltage drops, the luminaire adhering a instantaneous restrike device should be adopted on the HID lamp. And also, the scheme of extending a setting time of relay on the undervoltage relay and the forming method of sequence which is automatic reclosing at this time of instantaneous suspension of an electric supply have been studied.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.180-183
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• 2000

The Battery Energy Storage System(BESS) has lots of advantages such as load levelling, quick response emergency power(spinning reserve), frequency and voltage control, improvement of reliability, and deferred generation and transmission construction. The economic feasibility requires justification from the customer side of meter to promoting the dissemination of BESS nationally. In this paper, we proposed the economic assessment model of customer owned Battery Energy Storage System(BESS) which is complemented and improved the existing model. The proposed model is applied to the typical customer type(light-industrial commercial, and residential) which are taken from the statistical analysis on the load profile survey of Korea Electric Power COmpany (KEPCO). The economic assessment performed for each customer type to justifying their economic feasibility of BESS installation from the economic measures such as payback period, overall benefits, ROI, and ROR. The results of this paper are useful to the customer investment decision making and the national energy policy & strategy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1696-1702
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• 2008

This paper proposes a voltage compensation device direct control strategy to realize the distributed, autonomous voltage control of the distribution system, which based on voltage data collected from customers of the remote site under the ubiquitous-based distribution system. In the proposed method, The ULTC and the SVR(Step Voltage Regulator)s compensate autonomously the voltage for self-compensation area based on the voltage data furnished from the ubiquitous device of customers. Also, the SVRs overcome the limit of single-operation of ULTC by the interlocking operation with the ULTC and enhance the voltage compensation capability for the customer. In particular, an optimization design method and a fuzzy design method are compared to determine the effective control method of the voltage compensator under the ubiquitous-based on-line operation environments. In fuzzy method, the tap of voltage compensator is defined as output member. Finally, the proposed two methods are implemented in Visual C++ MFC, the effectiveness is proved by simulation based on the worst virtual voltage data. Also, an optimal voltage compensation strategy is determined under on-line environments based on analyzed results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.108-117
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• 2010

The main contents of this paper are the PQM system construction case and distribution system harmonic voltage analysis. The PQM system has constructed by KEPCO in order to investigate power quality of distribution power system for new power quality standard of KEPCO. In result, we have confirmed that voltage harmonic measurement value of the high voltage contract customer 8 households is suitable the KEPCO harmonic standard tentative plan. And the voltage harmonic value of distribution line end side is not always more high than source side by harmonic current offset effect. In the future, acquired data by season, region, load from the PQMS will be used on the resonable harmonic standard enactment in KEPCO.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.51-59
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• 2003

The utility and many customers employ capacitor banks(STATCON so called at the utility) to help control the power factor(customers) or voltage(the utility) by supplying reactive power to inductive loads. This paper presents analysis of transient overvoltages and harmonics due to utility STATCON switching. One simple and inexpensive means of limiting the voltage magnification transient and reducing harmonics is to switch the capacitor banks on a few minutes after the STATCON has been switched. Simulation results used the EDSA software package show the effects of decreased the transient voltage and harmonic reduction at the customer. And also harmonic limits based on the well-known international harmonic standards IEEE 519 and IEC 1000 are evaluated for the customer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.8
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• pp.113-120
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• 2007

This paper presents the electric shock hazards and solutions of loss of the combined protective and neutral (PEN) conductor in TN-C-S system. In order to mitigate the touch voltage on exposed-conductive-parts in a break in the PEN conductor, the touch voltages on exposed-conductive-parts in a break in the PEN conductor were experimentally investigated as a function of the ground resistances of the source grounding electrode and customer's additional grounding electrode. As a result, the equipotential bonding is one of important requirements for installations supplied by TN-C-S system. A solution of mitigating the touch voltages on exposed-conductor-parts caused by a loss of the PEN conductor would be the installation of the additional grounding electrode at the customer's service entrance. The ground resistance of additional grounding electrode necessary to limit the touch voltage to a safety voltage of less than 50[V] depends on the load and circuit parameters. In addition, the undervoltage sensing devices oner affordable solutions to detect a loss of the PEN conductor in TN-C-S system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.38-42
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• 2003

The use of VPI impregnated mica tape as high voltage insulation for large rotating electric machines requires a careful balance of processes and materials to obtain the desired electrical, mechanical and thermal characteristics. The stator insulation systems such as epoxy bonded high voltage mica tape have been produced for many years. One such system employing an epoxy and anhydride impregnating resin developed by Hyundai Heavy Industries, Co. (hereafter, HHI), to satisfy customer requests for an epoxy bonded insulation system. HHI applies the following electrical and thermal evaluations such as dielectric breakdown, voltage endurance, dissipation factor vs. temperature, isothermal weight loss, and so on. A detailed laboratory evaluation can describe specific physical limitations for an insulation system and permit development of long-term operation guidelines that permit full utilization of the proposed system. HHI has found these evaluations very helpful in qualifying insulation system for the repair of both large motors and generators.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.2
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• pp.88-93
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• 2005

Most of the LV customer have been applied the distribution system of 3-phase four wire system because of its advantage of supplying both of 1-phase & 3-phase loads simultaneously. Due to its structural simplicity, it is more convenient for use rather than the conventional separated scheme. But uneven load distribution or unclean voltage quality has occurred various problems such as de-rating, losses increase and vibration, etc. In this paper, voltage, current and power waveform in the actual fields have measured and analyzed in relation with internationally allowable voltage unbalance limits and compared the current unbalance factor with the load unbalance factor.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.110-112
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• 2003

This paper describes a detailed performance of induction motor with asymmetric voltage unbalance generated at the customer distribution system. The simulation results show that the change of current and torque, with the increase of unbalance factor, are more larger and has an important effect on load system.