著者

高野 富裕 松本 啓之亮 大木 功 大橋 敏明

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.115, no.7, pp.795-802, 1995-06-20 (Released:2008-12-19)

参考文献数

8

---

The authors have proposed a new framework of automatic knowledge acquision method and its prototype system has been reported at(6), which has generated switching sequences for substations. This paper will present its application to instruction table generation for local load dispatching offices. In the case of dispatching office the huge number and individual particularity are the points at issue. The office has to deal with hundreds of substations and transmission lines, and make a few hundreds of switching instruction tables a month. Generating tables is one of the most difficult tasks because the uniqueness of substations such as structural differences and particular management rules have prevented us from completing knowledge base which will contain thousands of rules. Our approach concerns the point for easy knowledge acquisition of the expert system, using an original learning algorithm named HCL (Hierarchical Concept based Learning). The HCL generates operational knowledge from cases in the past. This paper will discuss the fundamental problems of instruction table generation for dispatching offices and the solution to it by our approach. The method will be shown to construct and update its knowledge base automatically, using an actual network and operational cases of a dispatching office.

著者

横塚 勉

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B (ISSN:03854213)

巻号頁・発行日

vol.98, no.2, pp.169-176, 1978-02-20 (Released:2008-12-19)

参考文献数

9

著者

大城 諒士 我那覇 和奎 原田 繁実 金子 英治

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌. B (ISSN:03854213)

巻号頁・発行日

vol.136, no.2, pp.184-191, 2016

被引用文献数

3

---

In EMTP, it is very hard to simulate a vertically arranged cable, since its surge impedance gradually changes with the distance from the ground to a top point. In the past, some researches about surge impedances and responses of vertical conductor (for example transmission tower, concrete pole and so on.) have been carried out, these researches are being continued now. However, there is no model of vertical co-axial cable in EMTP. In order to analyze surge voltage arisen on the electrical system, approach of method for treating this model in EMTP is required. In this paper, experiments of surge impedance and response on vertical cable, method of treating for vertical co-axial cable in EMTP and accuracy confirmed as compared result of this model with analysis result of VSTL Rev. (Virtual Surge Test Lab. rev. ) which is constructed under FDTD (Finite Difference Time Domain) method, are reported.

著者

犬飼 道彦 西田 正 野呂 純 松田 明洋

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.123, no.9, pp.1040-1046, 2003 (Released:2004-05-28)

参考文献数

3

---

This paper describes the advance of the ground relay of the line protection.First of all, we examined the ground fault in a resistively grounded power system. The protective relay detects the ground fault by the zero phase current in the system. There are two methods for the current input to the relay. One uses the residual circuit of CT secondary winding, and the other uses the CT tertiary winding. When the ground current is insufficient in the residual circuit, the CT tertiary winding is used. In order to omit the CT tertiary winding and to get more reliability, we reviewed the full-scale of relay and evaluating the error of CT. As result, almost all transmission lines could omit the CT tertiary winding.Next, we examined the ground fault with high fault resistance in a solidly grounded power system. When that fault occurs in the system, the PCM current differential relay acts by fault current. So, this relay possibly mal-operates when the CT secondary circuit is disconnected. Therefore, it uses a special CT to raise the reliability. Nowadays GIS has become small and the CT installation space has been decreased, it is needed to reduce these CT cores. In order to omit the special CT, we utilized the combination of the power relay and the rate of change of relay current. As a result, there is a prospect that the relay would not need the special CT.These improvements are effective to reduce cost too.

著者

浅岡 由伸 本山 英器 松原 広治 杉本 仁志

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B (ISSN:03854213)

巻号頁・発行日

vol.125, no.10, pp.979-987, 2005

被引用文献数

1 3

---

Grounding resistance is one of the important parameters in the lightning-protection design of electric power systems. The grounding resistance of electrode decreases as large currents are injected to the electrode by electric discharges in soil. This characteristic is not considered in lightning protection design. Therefore, the design level is kept on the exceeding level in actual phenomena. From viewpoint of the rational lightning protection design for the electric power systems, this characteristic should be considered in practical design. In this study, experiments were conducted using rod electrodes, and the physical phenomena of the electrical discharge in soil were considered by assuming a certain electrical discharge model in soil. Based on these results, a grounding resistance large-current characteristic analysis model that could be easily used in EMTP was developed.

著者

金城 達人 千住 智信 上里 勝実 藤田 秀紀

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.124, no.8, pp.1059-1066, 2004 (Released:2004-11-01)

参考文献数

18

被引用文献数

5 8

---

The increased renewable energy utilization, especially photovoltaic panels using solar energy or wind turbine generators (WTGs) using wind energy, has been expected in recent years from view point of CO2 gas emission reduction and environmental conservation. However, the generated power is always fluctuating because the WTGs are driven by fluctuating wind. Therefore, an energy storage system should be installed to compensate these fluctuating elements. The energy capacitor system (ECS) which combined the electric double-layer capacitor (EDLC) and the electronic circuits are now under development. In this paper, control system configuration for active and reactive output power simultaneous control and the bi-directional inverter using current source EDLC are proposed. Moreover, we discusse control methods required in generating-power leveling for WTGs, and show the effectiveness of the proposed system through simulations.

著者

高橋 康人 徳増 正 藤田 真史 若尾 真治 岩下 武史 金澤 正憲

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B, 電力・エネルギー部門誌 = The transactions of the Institute of Electrical Engineers of Japan. B, A publication of Power and Energy Society (ISSN:03854213)

巻号頁・発行日

vol.129, no.6, pp.791-798, 2009-06-01

被引用文献数

25 5

---

This paper proposes novel techniques for the improvement of the convergence characteristic of step-by-step time integrations in nonlinear transient eddy-current analyses. The proposed methods, which are based on the time-periodic finite-element method and the explicit error correction method, can extract poorly-converged error components corresponding to large time constants of an analyzed system. The correction of the extracted error components accelerates the convergence of transient calculation efficiently. Furthermore, we extend the performance of the proposed methods in nonlinear problems. Some numerical results that verify the effectiveness of the proposed methods are also presented.

著者

川﨑 章司 田岡 久雄 長尾 泰気 大中 奎佑

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.135, no.2, pp.89-96, 2015 (Released:2015-02-01)

参考文献数

28

被引用文献数

1

---

Renewable energy sources such as photovoltaic generation (PV) have been promoted to be innovated. However, the output of PV is influenced by the weather condition and cause a steep fluctuation. So it is important to forecast the output of PV when an electric power company makes the power supply schedule for demand. In this paper, the authors proposed a forecasting method for amount of insolation closely related to the output of PV. In the proposed method, the amount of insolation is forecasted through the application of Genetic Algorithm which is one of the optimization method by using the past measured data. In addition, the correlation coefficients are analyzed with the weather data and measured insolation data. And, the correlation coefficients are used as the weight of observe value. The authors verify the validity and prediction accuracy of the proposed method. Moreover, we tried to improve the forecasting error by using the latest measured weather data and weather data of the other point.

著者

佐藤 伸治 小山 健一 糸谷 孝行 宮本 聖一 丸山 稔正

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B, 電力・エネルギー部門誌 = The transactions of the Institute of Electrical Engineers of Japan. B, A publication of Power and Energy Society (ISSN:03854213)

巻号頁・発行日

vol.123, no.4, pp.442-449, 2003-04-01

被引用文献数

4 6

---

We developed a multifunctional vacuum interrupter that has three functions: current interruption, disconnection, and earth operation in a vacuum vessel. Using the multifunctional vacuum interrupter, we realized 24 kV, 630 A, 25 kA rated switchgear that do not use SF<SUB>6</SUB> gas. In addition, we could downsize the switchgear greatly compared with conventional switchgear by applying excellent vacuum insulation characteristics. In this paper, we report the backgrounds and the solutions of the following technical problems regarding vacuum insulation inside the multifunctional vacuum interrupter: (1) Improvement of breakdown voltage between the vacuum vessel and high voltage flexible conductors, (2) optimization on the shape of shielding electrodes set at both ends of an insulating rod, (3) removal of conductive micro particles and improvement of breakdown voltage between contacts by using AC working voltage, and (4) identification of long-term reliability of vacuum insulation under the continuous application of AC working voltage.

著者

奥田 宏史 藤本 登 吉崎 政宣

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B (ISSN:03854213)

巻号頁・発行日

vol.98, no.8, pp.679-686, 1978-08-20 (Released:2008-12-19)

参考文献数

9

被引用文献数

2 2

著者

山城 迪 木下 尚 仲村 宏一 木村 貢 福島 知之

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.115, no.12, pp.1426-1431, 1995-11-20 (Released:2008-12-19)

参考文献数

10

---

Under the current deregulation of electric utility industry, power system planning has become more complex. System planners are required to study how to use the available resources to meet customer's demand economically with an acceptable reliability and quality. The integrated resource planning is emerged as one of the effective approach for this problem recently and the approach has been expanded to include the value of reliability, that is, power interruption cost. This paper is aimed to develop a flexible decision method to select a favorable plan among various transmission system expansion alternatives, not only from power supplier's view point, but also from customer's perspective including cost of interruption. Bellman-Zadeh's maximizing decision using fuzzy decision set is applied as an flexible decision method which is able to reflect the planner's intensions. Numerical examples are shown to ascertain the effectiveness of the proposed method.

著者

小西 義則 佐藤 学

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B (ISSN:03854213)

巻号頁・発行日

vol.133, no.5, pp.NL5_2-NL5_2, 2013

著者

千住 智信 金城 達人 上里 勝実 藤田 秀紀

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B, 電力・エネルギー部門誌 = The transactions of the Institute of Electrical Engineers of Japan. B, A publication of Power and Energy Society (ISSN:03854213)

巻号頁・発行日

vol.123, no.12, pp.1522-1530, 2003-12-01

被引用文献数

10 12

---

In recent year, power generation from renewable energy sources is comming up. Particularly, wind power generation is attractive because of it's advantages like, pollution free, no fuel cost, abundantly available in nature etc. However, the generated power is fluctuating and it mainly depends on the wind speed. These fluctuations will arise the bus voltage fluctuations and will cause power oscillations. A superconducting magnetic energy storage (SMES) unit based on a self-commutated inverter using Gate-turn-off (GTO) thyristor is capable of controlling both the active and reactive power simultaneously and quickly. <BR>In this paper, control system conguration for active and ractive output power control of the series and parallel compensator which applied SMES is presented. Furthermore, this paper also describes the effectiveness of generating power leveling of transmission line and compensation of the generator's terminal bus voltage instantaneous sag. It is show through simulations, that the controlling sequence of charging and discharging of the SMES coil effectively damps out the generator's terminal bus voltage fluctuations and transmission line power oscillations.

著者

石川 幸一郎 谷口 治人 鈴木 宏和 太田 豊 水野 陽二郎

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.134, no.7, pp.568-578, 2014 (Released:2014-07-01)

参考文献数

29

被引用文献数

6

---

Because of global warming, the attention to the photovoltaic generation has increased, and a lot of photovoltaic generations will be installed in the power system. In Japan, most photovoltaic generations will be connected to the distribution system. This will make the power flow in the power system changed. That is to say that the forward power flow (flow from higher voltage system to lower voltage system) reduces, or, moreover, that the reverse power flow occurs. Because of the change in power flow, the voltage characteristics will be also changed. Consequently, it is expected that the penetration of photovoltaic generation has some impacts on voltage stability. In previous study, the voltage characteristics in simple power system model which consists of one infinite bus, one load, and one photovoltaic generation is made clear. It is indicated from the results that there is not only forward power flow limit but also reverse power flow limit (left nose in PV curve), and that, when the output power from photovoltaic generation is very large, left nose sometimes has some impacts on voltage stability. In this paper, the voltage stability in the simple power system model considering the dynamics of an induction motor is discussed.

著者

石川 幸一郎 谷口 治人 鈴木 宏和 太田 豊 水野 陽二郎

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.134, no.1, pp.2-8, 2014-01-01 (Released:2014-01-01)

参考文献数

14

被引用文献数

2 9

---

Because of global warming, the attention to the photovoltaic generation has increased, and a lot of photovoltaic generations will be installed to the power system in future. In Japan, most photovoltaic generations will be connected to the distribution system. This will make the power flow in the power system changed. That is to say that the forward power flow (flow from higher voltage system to lower voltage system) reduces, or, moreover, that the reverse power flow occurs. Because of the change in power flow, the voltage characteristics will be also changed. Consequently, it is expected that the penetration of photovoltaic generation has some impacts on voltage stability. In this paper, simple power system model which consists of one infinite bus, one load, and one photovoltaic generation is considered, and the fundamental voltage characteristics are discussed by PV curves and phasor diagram. The voltage characteristics considering the current limit by PCS (Power Conditioning System) in the photovoltaic generation are also discussed.

著者

吉川 茂樹 北 裕幸 田中 英一 長谷川 淳

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.125, no.12, pp.1137-1145, 2005 (Released:2006-03-01)

参考文献数

23

被引用文献数

3 2 4

---

The authors have proposed the Flexible, Reliable and Intelligent ENergy Delivery System (FRIENDS) as a concept of future electric power systems. The concept of FRIENDS takes into account the deregulation of the electric power industry and progress of technologies such as power electronics, distributed generators (DG), distributed energy storage systems (ESS), information and communication. One of the most important characteristics of FRIENDS is that new facilities called Quality Control Centers (QCC) are installed between distribution systems and electric consumers.This paper presents a methodology for DSM based on a real-time pricing system through the information and communication network in FRIENDS. The economic use of DG and ESS in QCC is also considered in the proposed DSM. The sigmoid logistic function is used for modeling the real-time pricing system and a couple of parameters in the function are optimized by the Genetic Algorithm so that the profit of QCC is maximized. The effectiveness of the proposed DSM is ascertained by evaluating the profit or the load factor of QCC through simulations using model systems.

著者

辻本 富幸 中出 雅彦 八木 幸弘 石井 登

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B, 電力・エネルギー部門誌 = The transactions of the Institute of Electrical Engineers of Japan. B, A publication of Power and Energy Society (ISSN:03854213)

巻号頁・発行日

vol.126, no.4, pp.421-426, 2006-04-01

被引用文献数

3

---

Water tree is one of the degradation aspects of XLPE cables used for under-ground distribution or transmission lines. We have developed the loss current method using 3rd harmonic in AC loss current for cable diagnosis. Harmonic components in loss current arise as a result of the non-linear voltage-current characteristics of water trees. We confirmed that the 3rd harmonic in AC loss current had good correlation with water tree growth and break down strength. After that, we have applied this method to the actual 66kV XLPE cable lines. Up to now, the number of the application results is more than 130 lines.<br>In case of cable lines terminated at gas-insulated switchgear (GIS), we have to remove the lightning arrestor (LA) and the potential transformer (PT) out of the test circuit. The reason is that we are afraid that each of LA and PT disturbs the degradation signal from cable lines. It takes extra time (1 or 2 days) and costs more to remove LA and PT in GIS out of a circuit. In order to achieve easy and reasonable diagnosis, we have developed a new method for cable lines terminated at GIS, by utilizing a technique, which enables to reduce signal of LA and PT from disturbed signal of cable lines. We confirmed the effect of the new method by experiments with actual cables.

著者

久保 猛志

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.118, no.7-8, pp.750-753, 1998-07-01 (Released:2008-12-19)

参考文献数

2

著者

八木 幸弘 田中 秀郎 武藤 秀二 木村 人司

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.119, no.4, pp.438-444, 1999-04-01 (Released:2008-12-19)

参考文献数

11

被引用文献数

6

---

Degradation of XLPE cable by water trees gives rise to harmonics in the loss current. The authors are engaged in development of diagnostic methods for water tree degradation utilizing these harmonic components. As a result of this development, the following was discovered. The harmonic components occurring in the loss current provide an extremely good indication of the state of degradation. Harmonic components arise as a result of the nonlinear voltage-current characteristic of water trees. An equivalent circuit which incorporates this nonlinearity of water trees faithfully reproduces the loss current waveforms obtained in experiments. When a voltage at a frequency differing from commercial frequencies is superposed, a degradation signal occurs at a characteristic frequency.

著者

江川 正尚

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B, 電力・エネルギー部門誌 = The transactions of the Institute of Electrical Engineers of Japan. B, A publication of Power and Energy Society (ISSN:03854213)

巻号頁・発行日

vol.129, no.2, pp.253-256, 2009-02-01

被引用文献数

2 1

---

On July 23, 1987, a very hot day, the largest wide-area power outage occurred in Kanto-Area, Japan. The cause was a voltage collapse on the bulk power network of Tokyo Electric Power Company, due to the abnormal rate of demand rising following resume after lunch break. Aggressive studies on voltage collapse throughout industry and university have led to great advances in power system stability. This essay describes the detail record of the outage, the applied countermeasures, and the inside story when the multiple voltage solutions of power flow on actual power system were found out for the first time.