• Title/Summary/Keyword: voltage tap

Search Result 172, Processing Time 0.025 seconds

Development Pole Transformer with Automatic Tap Changer (자동 탭 절환 내장형 주상변압기 개발에 관한 연구)

  • Nam-Koong, Won;Lee, Sung-Woo;Jang, Moon-Jong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.27 no.9
    • /
    • pp.108-113
    • /
    • 2013
  • Change of supply voltage, customer load, output of distributed generation, etc cause voltage change in distribution system. OLTC and SVR are usually used to supply normal voltage at customer. But usage of these devices is inefficient and uneconomical in certain circumstances. To solve this problem, new pole transformer which has automatic tap changer is developed. The transformer changes tap when voltage changes. And it has latch switch and reactor for supplying power without outage. To verify normal operation of tap changer, test is conducted. SVR and 50kVA load is used for test.

The Maximum Installable DG Capacity According to Operation Methods of Voltage Regulator in Distribution Systems (배전계통의 전압조정기 운영방법에 따른 분산형전원 최대 도입 용량 산출)

  • Kim, Mi-Young
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.58 no.7
    • /
    • pp.1263-1269
    • /
    • 2009
  • Stable and sustainable power supply means maintaining a certain level of power quality and service while securing energy resource and resolving environmental issues. Distributed generation (DG) has become an essential and indispensable element from environmental and energy security perspectives. It is known that voltage violation is the most important constraint for load variation and the maximum allowable DG. In distribution system, sending voltage from distribution substation is regulated by ULTC (Under Load Tap Changer) designed to maintain a predetermined voltage level. ULTC is controlled by LDC (Line Drop Compensation) method compensating line voltage drop for a varying load, and the sending voltage of ULTC calls for LDC parameters. The consequence is that the feasible LDC parameters considering variation of load and DG output are necessary. In this paper, we design each LDC parameters determining the sending voltage that can satisfy voltage level, decrease ULTC tap movement numbers, or increase DG introduction. Moreover, the maximum installable DG capacity based on each LDC parameters is estimated.

Training an Artificial Neural Network (ANN) to Control the Tap Changer of Parallel Transformers for a Closed Primary Bus

  • Sedaghati, Alireza
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2004.08a
    • /
    • pp.1042-1047
    • /
    • 2004
  • Voltage control is an essential part of the electric energy transmission and distribution system to maintain proper voltage limit at the consumer's terminal. Besides the generating units that provide the basic voltage control, there are many additional voltage-controlling agents e.g., shunt capacitors, shunt reactors, static VAr compensators, regulating transformers mentioned in [1], [2]. The most popular one, among all those agents for controlling voltage levels at the distribution and transmission system, is the on-load tap changer transformer. It serves two functions-energy transformation in different voltage levels and the voltage control. Artificial Neural Network (ANN) has been realized as a convenient tool that can be used in controlling the on load tap changer in the distribution transformers. Usage of the ANN in this area needs suitable training and testing data for performance analysis before the practical application. This paper briefly describes a procedure of processing the data to train an Artificial Neural Network (ANN) to control the tap changer operating decision of parallel transformers for a closed primary bus. The data set are used to train a two layer ANN using three different neural net learning algorithms, namely, Standard Backpropagation [3], Bayesian Regularization [4] and Scaled Conjugate Gradient [5]. The experimental results are presented including performance analysis.

  • PDF

Voltage Measurement-based coordinated Volt/VAR Control for Conservation Voltage Reduction (CVR을 위한 전압 계측 기반 전압 및 무효전력 협조제어)

  • Go, Seok-Il;Choi, Joon-Ho;Ahn, Seon-Ju;Yun, Sang-Yun
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.66 no.12
    • /
    • pp.1689-1696
    • /
    • 2017
  • In this paper, the voltage measurement-based coordinated Voltage/VAR control (VMCVVC) algorithm for conservation voltage reduction(CVR) is proposed. The proposed algorithm has the purpose of enhancing the CVR effect through coordinated control of the voltage control devices such as the distributed energy resources and the load tap changer(LTC) transformers. It calculates the references of the voltage control devices such that the bus voltages are maintained at as close to the lower operation limit as possible. For this purpose, firstly, the distribution system is divided into LTC transformer control zones through topological search. Secondly, the reactive power references of the reactive power control devices are determined such that the voltage profile of the section is flattened. Finally, the tap references of the LTC transformers are calculated to lower the voltage profile. The effectiveness of the proposed algorithm is demonstrated through case studies using IEEE test network.

Performance improvement of PV_system's inverter that use transformer tap (변압기 탭을 이용한 태양광인버터의 성능개선)

  • Park Noh-Sik;Park Sung-Jun;Kim Kwang-Heon;Lim Young-Cheol;Kwon Soon-Jae;Kim Cheul-U
    • Proceedings of the KIPE Conference
    • /
    • 2004.07b
    • /
    • pp.511-514
    • /
    • 2004
  • Proposed about new inverter that can use in PV system in this paper. Multi_level inverter that used inverter makes use of 4 transformers is basis, primary winding of each transformer voltage as can do step_up or step_down to appropriate voltage space tap lake. Put circuit that tap that turn in transformer connects properly according to inhibit signal that sense change of input voltage (output voltage of solar cell place) and transformer secondary voltage controls point of contact of relay so that get into fixed output voltage. As a result, can minimise relative harmonic content despite change width of input voltage are wide because number of output voltage level of multi_level inverter does not decrease. Because proposed circuit manufactures is easy and control is easy and is no burden of cost price rise economically, commercialization expected to do easily and this study examined propriety of action as that compose and experiments proposed circuit.

  • PDF

Measurement of HTS Stacked Tapes Properties under Over-Current Condition in External Magnetic Field (외부자계 인가시 적층 고온초전도선재의 과전류 통전특성 측정)

  • Lee, K.Y.;Lim, H.W.;Lee, H.J.;Cha, G.S.;Lee, J.K.
    • Proceedings of the KIEE Conference
    • /
    • 2002.07b
    • /
    • pp.909-911
    • /
    • 2002
  • Rises of current level at power applications, such as transformer, motor, power cable need for using stacked HTS tapes. In this paper, we measured rises of temperature and tap voltage in 4-stacked HTS tapes under over-current condition. We measured 4-stacked HTS tapes properties under over-current condition with a little temperature rise as well as a large temperature rise. Rises of temperature and tap voltage are measured by using E-type thermocouples and voltage taps, respectively. According to the results of measurement, rises of tap voltage under over-current condition with a large temperature rises depends on rises of temperature.

  • PDF

Voltage Stability Analysis Based on Energy Function Considering Tap of Transformer (변압기 탭이 반영된 에너지 함수를 이용한 전압안정도 해석)

  • Lee Ki-Je;Choi Byoung-Kon;Kwon Yong-Jun;Moon Young-Hyun;Oh Yong-Taek;Lee Byunn-Ha
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.54 no.7
    • /
    • pp.337-344
    • /
    • 2005
  • An energy function is derived on the basis of the EMM(Equivalent Mechanical Model) to take account of the effects of tap changer, and then the VC(Voltage Collapse) criteria is proposed to predict the voltage collapse in Power systems. The VC criterion can be evaluated by using the energy margin given by the energy gap between UEP(Unstable Equilibrium Point) and SEP(Stable Equilibrium Point) of the energy function adopted, in which it is noted that the energy contour should be considered due to energy discontinuity associated with tap changing. This paper shows that the proposed VC criterion improves the accuracy of voltage stability analysis with application to a two-bus sample system.

Coordinated Control of the Under Load Tap Changer (ULTC의 협조제어)

  • 이송근
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.52 no.9
    • /
    • pp.500-505
    • /
    • 2003
  • The target of the ULTC(Under Load Tap Changer) control purpose is to minimize the operation number of the tap of the ULTC doing the error voltage which is the difference between the measured bus voltage End the reference bus voltage of the receiving end becomes less than the tolerance limits. The existing ULTC control method controls each ULTC considering only its bus voltage of the receiving end. However, this method did not cons der the coordinated control of the ULTCs of the system. In this paper, I proposed a coordinated control of the ULTC in :he loop power system using the Jacobian matrix. To show the validity of the proposed method, I made simulations for three cases: no action of the ULTC, the control of the ULTC by the existing control method, and the control of the ULTC by the coordinated control among the ULTCs of the system. The simulation result shows that the proposed method has more improvement of the operation of the ULTC than other methods.

Self-field Loss Characteristics of a long Bi-2223/AgMgNi Tape (장척 Bi-2223/AgMgNi 테이프의 자기자계손실 특성)

  • Ryu, Gyeong-U;Park, Gwon-Bae;Cha, Gwi-Su;Choe, Gyeong-Dal;Lee, Ji-Gwang;Han, Song-Yeop
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.49 no.4
    • /
    • pp.240-245
    • /
    • 2000
  • The self-field losses in a long multifilamentary Bi-2223/AgMgNi tape with varying transport current, voltage tap configurations, frequency and tape arrangements were investigated. Experimental results show that the measured losses are strongly dependent on voltage gap configurations but independent on tape arrangements. All voltage taps except the center tap are found to agree well with those predicted by Norris for an elliptical conductor. The self-field losses are purely hysteretic in nature in the range of applied frequencies for the transport currents below the critical current.

  • PDF

The On-Line Voltage Management and Control Solution of Distribution Systems Based on the Pattern Recognition Method

  • Ko, Yun-Seok
    • Journal of Electrical Engineering and Technology
    • /
    • v.4 no.3
    • /
    • pp.330-336
    • /
    • 2009
  • This paper proposes an on-line voltage management and control solution for a distribution system which can improve the efficiency and accuracy of existing off-line work by collecting customer voltage on-line as well as the voltage compensation capability of the existing ULTC (Under Load Tap Changer) operation and control strategy by controlling the ULTC tap based on pattern clustering and recognition. The proposed solution consists of an ADVMD (Advanced Digital Voltage Management Device), a VMS (Voltage Management Solution) and an OLDUC (On-Line Digital ULTC Controller). An on-line voltage management emulator based on multi-thread programming and the shared memory method is developed to emulate on-line voltage management and digital ULTC control methodology based on the on-line collection of the customer's voltage. In addition, using this emulator, the effectiveness of the proposed pattern clustering and recognition based ULTC control strategy is proven for the worst voltage environments for three days.