Hokuriku Electrical Power Company
Hokuriku Electrical Power Company
Kanao N.,Hokuriku Electrical Power Company |
Komami S.,Hokuriku Electrical Power Company
IEEJ Transactions on Power and Energy | Year: 2017
This paper describes a mechanism and its countermeasure of a hunting phenomenon caused by an anti-islanding scheme using a frequency feedback method of photovoltaic generation. It is known that the hunting phenomenon occurs when large PVs are connected to the end part of a long distributed transmission line, and it was observed in some experiments and simulations. But the hunting mechanism hasn't been clarified yet. The authors describe the hunting mechanism theoretically using a linearized model and a detailed model, and then check it by Nyquist plot and Y-ho simulation. The hunting is induced by a frequency positive feedback between power system and reactive power injected by the anti-islanding scheme. A simple and effective countermeasure is to add a first-order time delay to the signal of reactive power. © 2017 The Institute of Electrical Engineers of Japan.
Mitsubishi Group, Hokkaido Electric Power Co., Tohoku Electric Power Co., Tokyo Electric Power Company, Chubu Electric Power Co., Hokuriku Electrical Power Company, Kansai Electric Power Co., Chugoku Electric Power Co., Shikoku Electrical Power Co., Kyushu Electric Power, Electric Power Development Co., Japan Central Research Institute of Electric Power Industry and Clean Coal Power R&D Co. | Date: 2011-10-05
Provided is a ground flare in which a low-frequency vibration generated from a ground flare tower, such as a chimney, is properly adjusted to suppress it below a fixture-vibration generation limit, thereby preventing surrounding objects from resonating and vibrating. In a ground flare (10) that burns a flammable exhaust gas with a burner (11) at the lower end of a chimney, in which the lower end of the chimney (20) and the periphery of the burner (11) are surrounded by a windbreak (40), the low-frequency-noise sound pressure level of a ground flare tower composed of the chimney (20) and the windbreak (40) is reduced by selecting at least one of changing a natural frequency generated from the ground flare tower, using multiple ground flare towers, and installing a low-frequency-vibration absorber in the ground flare tower.
Mitsubishi Group, Clean Coal Power R&D Co., Hokkaido Electric Power Co., Tohoku Electric Power Co., Tokyo Electric Power Company, Chubu Electric Power Co., Hokuriku Electrical Power Company, Kansai Electric Power Co., Chugoku Electric Power Co., Shikoku Electrical Power Co., Kyushu Electric Power, Electric Power Development Co. and Japan Central Research Institute of Electric Power Industry | Date: 2011-06-15
It is possible to prevent a phenomenon by which the wall temperature of an outer cylinder rises abruptly as a layer of steam covers the inner circumferential surface of the outer cylinder and therefore decreases the heat transfer coefficient thereof, thus preventing a heat damage to the outer cylinder. Also prevented is burnout of the burner resulting from insufficient cooling due to variations in cooling efficiency at a leading end of the burner. A leading end located in a two-stage entrained-flow bed coal gasifier has a double-walled structure including an outer cylinder and an inner cylinder, and cooling water for cooling the leading end is supplied through an interior of the inner cylinder to cool the leading end and is then returned to a base end through a space formed between the outer cylinder and the inner cylinder. The space formed between the outer cylinder and the inner cylinder has a smaller channel area than the interior of the inner cylinder, and a swirling flow along a guide formed on an outer circumferential surface of the inner cylinder and a substantially linear flow in a longitudinal direction of the outer cylinder and the inner cylinder are applied to the cooling water returned to the base end through the space formed between the outer cylinder and the inner cylinder.
Mitsubishi Group, Hokkaido Electric Power Co., Tohoku Electric Power Co., Tokyo Electric Power Company, Chubu Electric Power Co., Hokuriku Electrical Power Company, Kansai Electric Power Co., Chugoku Electric Power Co., Shikoku Electrical Power Co., Kyushu Electric Power, Electric Power Development Co., Japan Central Research Institute of Electric Power Industry and Clean Coal Power R&D Co. | Date: 2012-07-25
A slag monitoring device 100 for a coal gasifier includes a slag hole camera 11 that observes a slag hole 3 from which molten slag flows out, a water surface camera 12 that observes a situation in which the slag flowing out from the slag hole 3 falls onto a water surface 5H of cooling water 5, a falling sound sensor 13 that observes a sound of the slag falling onto the water surface 5H, and a processing device 20 that determines a solidification and adhesion position of the slag based on an opening area of the slag hole 3 observed by the slag hole camera 11 and falling lines and falling positions of the slag observed by the water surface camera.
Hashimoto T.,Hokuriku Electrical Power Company |
Torii K.,Kanazawa University
Journal of Advanced Concrete Technology | Year: 2013
In the Hokuriku district, the effort toward the production of highly durable concrete mixtures using classified fine fly ash has just started as a part of ongoing countermeasures for the chloride attack and the alkali silica reaction (ASR). At a time when ASR deterioration phenomena are still progressing, the use of fly ash cement in concrete should be recommended and assertively be adopted as a regional approach for the mitigation of ASR problem especially in the Hokuriku District. In order to promote this mutual understanding and cooperation among the electric power companies, the national and local governments, the industrial association of ready-mixed concrete companies and the universities are indispensable. Accordingly, a joint-collaborative industry-academia-government research committee has been set up in January 2011. This paper focuses on the drawing from the current stage of ASR problem in the Hokuriku district and the development of highly durable fly ash concretes as its countermeasures. Copyright © 2013 Japan Concrete Institute.
Sugimoto H.,Hokuriku Electrical Power Company
IEEJ Transactions on Power and Energy | Year: 2010
Distribution surge arresters are often damaged by lightning strokes, in particular, winter lightning. An overhead ground wire (OGW) is one of effective measures against surge arrester failures. However, adding the conventional OGW to existing overhead power distribution lines needs the power interruption for construction as well as high costs because of installing them above phase conductors. Experimental results show that a covered conductor for distribution lines is more difficult to attract lightning than a bare conductor. Moreover, lightning strokes to distribution pole heads occupied over 90% of all lightning strokes in the observation result of lightning strokes to actual distribution lines without the conventional OGW, and lightning strokes to power lines were hardly observed. These results indicate that the pole heads shield the power Unes from direct lightning strokes. Therefore the author studies the application of an OGW under the distribution lines (UGW) for reducing surge arrester failures. The lightning performance of the UGW is estimated by the Electro-Magnetic Transients Program (EMTP) and its effectiveness is demonstrated. The measure is expected to cut costs of construction and maintenance for lightning protection. © 2010 The Institute of Electrical Engineers of Japan.
Yamagishi Y.,Hokuriku Electrical Power Company |
Fujii Y.,University of Tokyo
IEEJ Transactions on Power and Energy | Year: 2012
High penetration of renewable energy may affect electric power system, because the variations in renewable energy power generations are affected by climate and relatively higher than those of conventional plants. Meanwhile, the future of global economic conditions and technological progress are very large uncertainties. It is difficult to find out the optimal solution based on current conditions. In this paper, an optimal power generation mix model is proposed, which can properly deal the essence of real conditions and carry out a number of simulations efficiently. In order to illustrate the proposed model, several parameter analysis cases, such as CO 2 emission constraints, fuel prices, costs of PV and storage facilities, and differences by years are studied. © 2012 The Institute of Electrical Engineers of Japan.
Shibata H.,Hokuriku Electrical Power Company
IEEJ Transactions on Power and Energy | Year: 2015
Traditionally, there are close relation between load dispatching operation of power system and meteorological phenomena, such as demand fluctuation and temperature, hydro power generation fluctuation and precipitation, and faults and extreme weather like lightnings or typhoon. Load dispatching operators of power system, by gathering and utilizing available meteorological information, continuously monitor the constantly changing power demand and the power plant operation level to perform power supply demand management and power system operation. Considering the evolving environment of the load dispatching operations, our R&D Investigation Committee examined the relation between load dispatching operation and meteorological information, the collection method and utilization of meteorological information, and the changes in load dispatching operation caused by the further introduction of renewable energy. Moreover, we have summarized possible issues and future visions on the expansion of renewable energy. © 2015 The Institute of Electrical Engineers of Japan.
Nagoya H.,Hokuriku Electrical Power Company |
Komami S.,Hokuriku Electrical Power Company |
Ogimoto K.,Tokyo University of Science
IEEJ Transactions on Electronics, Information and Systems | Year: 2011
Mutual smoothing effect of renewable energy (RE) is quite important because amount and cost of countermeasure for maintaining soundness of power system highly depend on evaluation of the effect. In spite of the importance, there is no established method to evaluate the effect yet. The paper presents a method for presuming total output fluctuation of highly penetrated RE from few measured data considering the effect. By analyzing measured data, existing photovoltaic (PV) output fluctuation is revealed to be coherent at slower swing period and random at faster. To represent the PV's output fluctuation tendencies, "Transfer Hypothesis" is introduced. "Constant transfer swing period hypothesis" and "-20dB/dec slope hypothesis" are supplementary introduced. Those hypotheses are verified by direct and indirect methods using the measured data. Only 3 sites' data are able to presume total fluctuation of 15 sites successfully. Relationship of distance and transfer swing period of every 2 sites out of the 15 sites agrees to those hypotheses. Finally, the paper shows total fluctuation presumption of highly penetrated PV in Hokuriku region using proposed methods. © 2011 The Institute of Electrical Engineers of Japan.
Fuji Electric Co. and Hokuriku Electrical Power Company | Date: 2012-02-03
The disclosed distributed power supply system does not become disconnected from a grid simultaneously with others when the grid voltage falls instantaneously. In a distributed power supply device which controls an inverter circuit 10 based on a control signal obtained by comparing a predetermined carrier signal and voltage command signals of three phases and which converts DC power to AC power and supplies the AC power to a power grid of a three-phase AC power supply, fundamental wave signals of three phases are generated from a grid voltage of the three-phase AC power supply. A reference cosine wave signal is generated from the fundamental wave signals of three phases. A third harmonic signal is generated from the reference cosine wave signal and the fundamental wave signals of three phases. The three-phase fundamental wave signals and the third harmonic signal are added to generate voltage command signals of three phases.