• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.2
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• pp.74-80
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• 2014

Generator protection device has to detects an internal fault conditions in generator and abnormal operating conditions must be due to the hazards. Loss of excitation may cause generator itself failure as well as serious operating problem in power system, and then requires an appropriate response of generator protection device. Details modeling of generator control system and analysis of transient states in generator are important for optimal operation in power plants. In addition, the fault simulation data are also used for testing the characteristics of IED. In this paper, the hydro generator control system using PSCAD/EMTDC, visual simulation for power systems, was modeled. The generator control system which is composed of generator, turbine, exciter, governor was implemented. The parameters of generator control system model were obtained from field power plant. Loss of excitation simulations were performed while varying the fixed load. Several signals analysis were also performed so as to analyze transients phenomena.

• International Journal of Fluid Machinery and Systems
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• v.8 no.1
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• pp.46-54
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• 2015

Thrust-ring-pump is a kind of extreme-low specific speed centrifugal pump with special structure as numerous restrictions from thrust bearing and operation conditions of hydro-generator units. Because the oil circulatory and cooling system with thrust-ring-pump has a lot of advantages in maintenance and compactness in structure, it has widely been used in large and medium-sized hydro-generator units. Since the diameter and the speed of the thrust ring is limited by the generator set, the matching relationship between the flow passage inside the thrust ring (equivalent to impeller) and oil bath (equivalent to volute) has great influence on hydrodynamic performance of thrust-ring-pump. On another hand, the head and flow rate are varying with the operation conditions of hydro-generator units and the oil circulatory and cooling system. As so far, the empirical calculation method is employed during the actual engineering design, in order to guarantee the operating performance of the oil circulatory and cooling system with thrust-ring-pump at different conditions, a collaborative hydrodynamic design and optimization is purposed in this paper. Firstly, the head and flow rate at different conditions are decided by 1D flow numerical simulation of the oil circulatory and cooling system. Secondly, the flow passages of thrust-ring-pump are empirically designed under the restrictions of diameter and the speed of the thrust ring according to the head and flow rate from the simulation. Thirdly, the flow passage geometry matching optimization between thrust ring and oil bath is implemented by means of 3D flow simulation and performance prediction. Then, the pumps and the oil circulatory and cooling system are collaborative hydrodynamic optimized with predicted head-flow rate curve and the efficiency-flow rate curve of thrust-ring-pump. The presented methodology has been adopted by DFEM in design process of thrust-ring-pump and it shown can effectively improve the performance of whole system.

• The KSFM Journal of Fluid Machinery
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• v.16 no.5
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• pp.11-17
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• 2013

This study is aimed to construct a marine small hydro power plant using discharge water of fish farm in Jeju Haengwon-ri. The difference of design methods between marine small hydro power plant and land small hydro power plant is to consider the tides. Moreover, ground condition should be examined because gushout sea water comes out from the ground at high tide in Jeju as the ground of Jeju beach consists of basalt stone. From the field test of the turbine generator after construction of the power plant, output power and efficiency of the turbine generator shows good conformance to the required conditions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.689-693
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• 2015

Recently, many advanced countries are devoted to the development of eco-friendly new-renewable energy to prepare for the depletion of resources. Korea belongs to the absolute lack of energy to import from abroad 97% of energy use. So, development and supply of eco-friendly energy such as small hydro power has been required even more. Our country has a large number of small-sized reservoirs and dams. So, hydro generator has been installed at the small reservoirs and dams with the economy. Since the discharge flow of agricultural reservoir is not constant, the guide vane of wicket gate is used for adjusting the output of the generator.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.8
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• pp.1134-1139
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• 2014

Recently the need for renewable energy development is expanding due to the global climate change, the environmental issues and the limited fossil energy resources. Dependence of energy on overseas is high in Korea. To resolve the environmental problems and to improve the energy independence rate, the development of renewable energy is more required. The small hydro power, one of the renewable energy resources, has been developing and operating from a long time ago. If we are new developing a small hydro power with the use existing dams and reservoirs, we will design the length of inlet pipe and the diameter suitable for it. However, in case of using the existing water supply pipe which had been designed suitable for water service, the designer has to review and check that the pipe is suitable for operating a generator. In this paper, the design of small hydro power using the existing long pipe of water supply, we suggest the optimum way to reduce the water hammer in pipe which causes the unsteady flow during the load-shutdown of generator, the generator operation plan for the stable supply of water and the design factor of determining the generator capacity through the analysis between discharge and head-loss.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1526-1529
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• 1994

In hydro-generator, a groundwall insulation of stator windings gradually deteriorates due to mechanical, thermal, electrical and environmental stresses. These stresses combine to result in loose windings, delamination of the stator insulation and/or electrical tracking of the end winding, all of which can lead to stator insulation failures. Conventionally, off-line tests such as partial discharge measurement, DC/AC current test and ${\Delta}tan{\delta}$ test has been used for estimation of winding condition. However, off-line test requires large power supply and generator outage. In addition, major cause of insulation problems such as loose wedges and slot discharges may not be found with off-line diagnoses. This paper describes the on-line partial discharge measurement techniques in the generator stator windings. The experimental results from the UIAM #1 hydro-generator confirms a optimistic application of on-line generator diagnosis method as a reliable tool for evaluation of winding condition.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.3
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• pp.159-163
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• 2015

Recently squirrel cage induction generator has been steadily applied to many small hydro power plants. Induction generator needs a reactive power for magnetization. The reactive power of induction generator is being supplied from the supply side mostly. The use of induction generators in the power distribution grid can affect the power factor. The power factor of induction generator is fixed already during production. The power factor in the distribution system is due to the increase or decrease of the load rather than due to the induction generator. In this study, we analyzed that how the increase or decrease of D/L load impacts at the change of power factor and power flow.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1507-1513
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• 2010

The $CO_2$ emission can be decreased due to freedom of generator maintenance scheduling(GMS). This paper proposes assessment of $CO_2$ emission considering generator maintenance scheduling(GMS) and evaluates effect of the GMS on $CO_2$ emission. And also, this paper assesses the $CO_2$ emission and the probabilistic production cost simulation of nuclear and thermal power generators considering operation of hydro and pumped generator. The minimum reliability criterion level satisfied production cost minimization function model is used in this paper. The practicality and effectiveness of the proposed approach are demonstrated by simulation studies for a real size power system in Korea in 2010.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.5
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• pp.632-638
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• 2013

In this study, we described voltage fluctuation characteristics of distribution line during starting and normal operation condition of the small hydro generators. Based on these theories, we scrutinized the starting and operating characteristics of induction generators installed in two small hydro power plants that is connected to the distribution line and researched necessary factors when selecting the generator type. The type of turbines and capacity of generators are different. One is below 1,000kW and the other is above 1,000kW. Two generators are tested during starting, and it acts as motor not generator at the instant that the machine is connected to the grid. After connecting to the grid, the machine rotates above synchronous speed before converting to the generator mode. Therefore the characteristic of the generator during starting is same as it of motor.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1100-1104
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• 2009

As national power consumption every year increases, the power plant which is in the process of planning tries to establish high-capacity generator. The power system tends to become a large size. With the progress of electronic components, the control systems of the generator have been digitalized and rapid-response control system is possible. However, the minute frequency vibration of grid occurred with the effect of rapid-response control system. To solve these problem, PPS(Power System Stability) has been introduced since 2004, and it has being installed and applied to the thermal and nuclear power plant which are high-capacity, over 800MVA. However the minute frequency vibration is gradually changed to the bigger frequency vibration by fast-action control system, and this regional frequency fluctuation might be diffused wide area. Therefore, it is applied to the hydro generator which is small with fast-action governor system, and it is necessary to control the minute frequency vibration to prevent to diffuse. In this paper, the effect will be proved by establishing PSS on the Hydro-Generator which has both digital excitation and governor system for the first time in Korea.