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Study on coordination of protective relays in distribution system with distributed generation
(2020-01-01)
Ananwattanaporn, Santipont
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Songsukthawan, Panapong
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Yoomak, Suntiti
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Pothisarn, Chaichan
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Jettanasen, Chaiyan
In the recent decade, many countries around the globe have been increased the proportion of electrical power generation from renewable energy sources, which results in rising in the penetration level of distributed generation (DG). However, the installation of DG into the distribution system may raise many issues that can impact the distribution system in both the technical and economic aspects. When DG is connected to a distribution system, it can affect the performance of the system and the protective device already installed owing to the change of voltage level, short-circuit level and direction of power flow in the system. For this reason, a protective device may cause the malfunction because the bus impedance of the system is changed; this will result in a change of the current in each bus. This paper aims to study the coordination between the protective relay and the DG installed into the distribution system. The distribution system under investigation is a part of the Provincial Electricity Authority (PEA). Under this research, DG data that are connected to the PEA distribution is used. The simulations are performed using digital simulation and electrical network calculation program (DIgSILENT).
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Fault classifications in distribution systems consisting of wind power as distributed generation using discrete wavelet transforms
(2019-12-01)
Patcharoen, Theerasak
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Ngaopitakkul, Atthapol
This paper proposed a fault type classification algorithm in a distribution system consisting of multiple distributed generations (DGs). The study also discussed the changing of signal characteristics in the distribution system with DGs during the occurrence of dierent fault types. Discrete Wavelet Transform (DWT)-based signal processing has been used to construct a classification algorithm and a decision tree to classify fault types. The input data for the algorithm is extracted from the three-phase current signal under normal conditions and during fault occurrence. These signals are recorded from the substation, load, and DG bus. The performance of the proposed classifying algorithm has been tested on a simulation system that was modeled after part of Thailand's 22 kV distribution system, with a 2-MW wind power generation as the DG, connected to the distribution line by PSCAD software. The parameters that were taken into consideration consisted of the fault type, location of the fault, location of DG(s), and the number of DGs, to evaluate the performance of the proposed algorithm under various conditions. The result of the simulation indicated significant changes in current signal characteristics when installing DGs. In addition, the proposed algorithm has achieved a satisfactory accuracy in terms of identifying and classifying fault types when applied to a distribution system with multiple DGs.
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A battery energy storage system control technique with ramp rate and C-rate parameter consideration for AC microgrid applications
(2018-01-01)
Prompinit, Krisada
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Khomfoi, Surin
Active power control of a battery energy storage system (BESS) in an ac microgrid to solve an impact of increasing of renewable energy resources (RES) is presented. The variability of active power from these renewable energy resources affects the reliability of the power grid. A BESS is used to connect with an ac microgrid consisting of RES such solar cells to manage the rapid change in flow of active power, so the output active power from RES is regulated within the standard for connecting to the Thailand grid-connected code. Ramp rate effects and characteristics of a battery used in a BESS are considered in proposed control strategy to control the flow of active power. The micro energy management system (μEMS) for calculating the appropriate active power slope is also developed. Therefore, the frequency deviation in the microgrid is regulated by using a proposed both control technique and μEMS. The control of this method ensures that the frequency stability is within the standard range of ±1 Hz in a 50 Hz system. Simulation and experimental results of the proposed method are good agreement, and the active power of the BESS in an ac microgrid can be satisfactorily controlled.
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Influence of wind farm on distribution system: Current characteristics during fault occurrence
(2018-01-01)
Ananwattanaporn, Santipont
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Ngaopitakkul, Atthapol
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Jettanasen, Chaiyan
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Pothisarn, Chaichan
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Leelajindakrairerk, Monthon
In this past few years, installation of distributed generator (DG) has become topic of interest in many countries due to rapid increase in energy and environmental issue. Generating power from renewable source has been proposed to compensate fossil fuel that is currently depleted. Wind power is one of the renewable energy sources that gains a huge attention, and many utilities are connecting wind power to distribution system. This number is going to get higher in the near future. Research on influence of wind power on system must be done in order to ensure the reliability of power system. This paper aims to study an impact of wind power-integrated distribution system when fault occurs in the system for various conditions. Many factors capable of changing system characteristics have been taken into account such as distribution system consisting of multi-wind power generation, size of wind power generation, fault type, and location of fault. Distribution system under this study is modeled based on 22 kv distribution network of Provincial Electricity Authority (PEA) in Thailand. Simulation will be done by using PSCAD/EMTP. Result obtained from case studies will be used to analyze and evaluate the effect of installation of wind power. The result indicates that the DG contributes significant fault current to the system when fault occurs.
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Study of the effects of protective device comprising distributed generation is connected in distribution system
(2013-07-12)
Muangchareon, Sujarit
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Ngaopitakkul, Atthapol
This paper proposes to study the effects of protection system, when 8 MW synchronous generator interconnected to distribution System of PEA. The three phase fault is simulated using digital simulation and electrical network calculation program (DIgSILENT). The type and size of conductor, distance of distribution line, location of protection device, maximum power of load, and location of load that are parameter of PEA, are investigated. The results are shown that, in case of DG interconnecting with distribution system, if a fault occurs, fault current is increased and fault current from substation is decreased. It causes to maloperation of protective device.
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Development of recloser coordination programming for distributed generation islanding distribution network
(2013-07-12)
Muangchareon, Sujarit
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Ngaopitakkul, Atthapol
When faults occur during islanding, faults should be eliminated before the power system is unstable. An islanding system is normally a weak system. The setting of protective devices should be completed before going back to the normal operation. This paper focuses on the impact of protective device when distributed generation is considered in islanding condition, then resulting in protection of the electrical system malfunctions. To overcome this problem, the setting of recloser coordination is investigated in this paper. The fault current and protection coordination is considered for protective device. The results show that the setting recloser for islanding condition, when recloser is set using proposed technique, it can reduce complexity and increase security of recloser.
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Electrical line losses indistribution system with the inclusion of very small power producer
(2012-06-12)
Chiradeja, Pathomthat
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Pothisarn, Chaichan
Distributed generation is becoming increasingly attractive to the power industry. Several distributed generation technologies such as wind energy systems, solar energy systems, biomass, and biogas are becoming economically viable. Thai government by the Department of Alternative Energy Development and Efficiency has issued the Renewable Energy Development Plan (REDP) in order to promote the usage of renewable energy. In addition, a policy that aims to increase the electric power generation from renewable energy is to expand the amount of electrical power to connect to the distribution system. After the implementing of this policy, both of the numbers and generation capacity of distributed generation who are willing to sell the electric power are significantly increasing. Under this policy, very small power producer (VSPP) has to pay the fee of 2% of its electrical energy sold to electricity utility. The main purpose of this fee is to cover the electrical line losses due to the employment of distributed generation (DG) or VSPP. However, the suitable and fairness for both VSPP and utility is still questionable. The goal of this paper is to analyze the effect of electrical line losses with the installing DG or VSPP into the distribution system. The results of this paper can be used and created the suitable and fairness of the fee for both VSPP and utility.
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An open circuit fault diagnostic technique in IGBTS for ac to dc converters applied in microgrid applications
(2011-01-01)
Khomfoi, Surin
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Sae-Kok, Warachart
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Ngamroo, Issarachai
An open circuit fault diagnostic method in IGBTs for the ac to dc converters used in microgrid applications is developed in this paper. An ac to dc converter is a key technology for microgrids in order to interface both distributed generation (DG) and renewable energy resources (RES). Also, highly reliable ac to dc converters are necessary to keep converters in continuous operation as long as possible during power switch fault conditions. Therefore, the proposed fault diagnostic method is developed to reduce the fault detection time and to avoid any other fault alarms because continuous operation is desired. The proposed diagnostic method is a combination of the absolute normalized dc current technique and the false alarm suppression algorithm to overcome the long fault detection time and fault alarm problems. The simulation and experimental results show that the developed fault diagnostic method can perform fault detection within about one cycle. The results illustrate that the reliability of an ac to dc converter interfaced with a microgrid can be improved by using the proposed fault diagnostic method.
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PEA guidelines of impact study and operation of DG for islanding operation
(2007-12-01)
Fuangfoo, Pradit
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Meenual, Thongchai
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Lee, Wei Jen
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Chow-Chompoo-Inwai
Since intentional islanding operation of Distributed Generation (DG) can increase system reliability, and reduce the customer outage cost due to loss of power supply from main grid, some utilities may permit islanding operation of DG. As a result, the impact study and operation criteria of DG for island operation should be performed. Provincial Electricity Authority (PEA) is increasingly interested in islanding operation. In order to perform islanding operation, PEA has to establish the islanding operation and impact study guidelines of DG. This paper presents the development of these guidelines. The study case is conducted to demonstrate results of impact study of both steady-state and dynamic analysis. The operation issues also take into account in this paper. ©2007 IEEE.

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