Tohoku Electric Power Company Research Articles

Supplementary Remarks on Lessons Learned from the Great East Japan Earthquake

Abstract: This paper takes a broad look at non-nuclear socio-technical systems that demonstrated highly resilient behavior during and after the Great East Japan Earthquake and tsunami. The lessons described in the accompanying papers are re-examined in conjunction with the responses exhibited by various organizations. After a preliminary review of cases from various sectors, a more detailed review was conducted on the activities of three organizations: Tohoku Electric Power Company, the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and the Ishinomaki Red Cross Hospital. Through this review, which was carried out based on the guidelines provided from Resilience Engineering, it became evident that valuable lessons are effectively derived from good practices emergently conducted during and after the earthquake and tsunami.

A112 新仙台火力発電所第3号系列における熱効率向上への取組みについて(OS1 次世代型火力発電システム技術)

For the simultaneous achievement of stable electricity supply and carbon dioxide emission reduction, Tohoku Electric Power company is proceeding the construction of Sin-Sendai Thermal Power Station Unit No.3 series (Output: 490MW×2), which are large-capacity gas turbine combined-cycle (GTCC) and replace from aged Unit No. 1 and No.2. Unit No.3 series which are adopted the latest gas turbine firing 1500℃ class turbine inlet temperature (TIT) are planned to achieve the highest level of thermal efficiency in the world (more than 60%LHV). In addition, reflecting our operation and maintenance knowledge in the design stage made it possible to enhance the thermal efficiency still more, which contribute to economy and environmental impact reduction.

家庭用燃料電池による電力需要のピークカットに関する研究

One of the effects of the 2011 Tohoku earthquake and the subsequent power disruptions was an increased demand for electricity. As a result, there have been societal efforts to reduce electricity usage and to provide electrical power more equitably. Private power generation by a fuel cell cogeneration system (FCCGS) recently proposed for home use is expected to advance the efficient utilization of primary energy sources and contribute to energy conservation. In this paper, we present the results of a case study on peak electricity demand by modeling the district served by the Tohoku Electric Power Company. The study analyzes the effects on peak power demand if residences in the district were equipped with FCCGSs. For this study, we assume that the FCCGSs are installed in groups of 100,000 units. The groups are composed of FCCGS units with different rated outputs whose hours of operation throughout the day are distributed among the groups. Power supply, primary energy consumption, and CO2 emission amounts both before and after the installation of FCCGSs are recorded in order to quantify the cut in peak demand for electricity. The results of the study demonstrate that peak demand can be cut if FCCGSs are installed in 5% or less (in winter) and about 25% (in summer) of all the private residences in the district served by Tohoku Electric Power Company

Improved Detection of Winter Lightning in the Tohoku Region of Japan using Vaisala’s LS700x Technology

Lightning Locating Systems (LLS) provide valuable information to a wide variety of applications. The demand for both data quality and the range of Cloud-to-Ground (CG) lightning parameters is highest for forensic applications within the electric utility industry. For years, the research and operational communities within this industry in Japan have pointed out a limitation of these LLS systems in the detection and location of damaging (high-current and large charge transfer) lightning flashes during the winter months (so-called “Winter Lightning” Ishii, 2006; Ishii and Saito, 2009; Honma, this conference). Most of these flashes appear to be upward-connecting discharges, frequently referred to as “Ground-to-Cloud” (GC) flashes. The basic architecture and design of Vaisala’s new LS700x lightning sensor was developed in-part to improve detection of these unusual and complex flashes. Toward this end, Vaisala has been involved in a multi-year collaboration with Tohoku Electric Power Company (Japan) and Sankosha Corporation. The specific objectives of this collaboration are (1) to carry out field experiments to provide a large number of transmission-line fault cases with time-correlated field waveforms; (2) to determine a method to classify the fault-causing flashes as CG or GC; and (3) to develop and test improvements to the LS sensors and location processing aimed a detecting, locating, and classifying these flashes. This paper presents our progress-to-date on the third element of this collaboration. We include an overview of the LS700x architecture, discuss how this architecture was exploited to evaluate and improve performance for winter lightning, and presentation of preliminary results on performance improvement. A companion paper at this conference (Honma, 2010) focuses on the first two elements of this collaboration.

S082012 次世代ガスタービン開発への取り組みと東北電力コンバインドサイクル発電プラントの歩み([S08201]高効率火力発電およびCCS技術)

As global warming becomes increasingly serious, resources and energy utilizations should be more efficient than before. Tohoku Electric Power Company, Inc. (Tohoku-EPCO) and Mitsubishi Heavy Industries, Ltd. (MHI) have started a study of next generation gas turbines to further improve the gas turbine combined cycle (GTCC) power plants efficiency. Tohoku-EPCO and MHI have invented a "closed circuit air cooling system" and a trial design of the closed circuit air cooled combustor is now being conducted as a collaborative project. Besides, the material technology development is being conducted for the further increase in the turbine Row 1 vane inlet temperature (TIT) in future.

A110 出力変動緩和型風力発電設備(OS2 再生可能エネルギー・マイクログリッド),動力エネルギーシステム部門20周年,次の20年への新展開)

Especially, the installation of the wind power generation with high cost-effectiveness is top priority to solve exhaustion of fossil fuels, CO_2-reduction while the importance of renewable energy installation rises. However, the load change is absorbed with expanding the wind power installation in the electricity system. So, Electric Power Company cannot help limiting the wind power installation from the viewpoint of the frequency change control. Agency for Natural Resources and Energy came up with the method in 2004 and reported that the use of the ream system line between electric power companies and output fluctuation relief by battery energy storage system are efficient measures. At the same time, Tohoku Electric power Company accepted wind power connected candidates with this technical requirement in 2006. Therefore, our company has developed a wind power generation system by optimizing wind turbine power limitation system and battery energy storage system, and we have evaluated that performance by our simulation. After that, we have constructed the Shiura wind farm with this system in Gosyogawara city since April 2009, and now, commercial operation started in February 2010. In this thesis, we introduce the outline of our system and we report the evaluation of the output fluctuation actual data in the Shiura wind farm.

混合粒径砂３次元海浜変形モデルのベクトル並列計算

Simulating 3-D beach deformation numerical model with usual scalar computer, computation load is considerably heavy even for prediction of seabed evolution in the region of 4 kilometers around coastal structure in interval of 1 year. However, introducing vector-pararel computation suitable for each sub-model consisting of beach deformation model, computation performance can be efficiently increased. In this paper, a methodology of vector-pararel computation for 3-D beach deformation model subject to sediment sand of mixed grain size is investigated and proposed. This numerical model is applied to a field site of sea area around the Higashidori power plant of the Tohoku Electric Power Company and effect of vector-pararel computation is verified.

The development of effective heat and power use technology for residential in a PEFC co-generation system : Inaka, H. et al. Journal of Power Sources, 2002, 106, (1–2), 60–67

This paper describes recent activities on wind energy in Japan. The national “Sunshine Project” conducted by the Ministry of International Trade and Industry, was reviewed in 1990 to map out a new energy strategy in the Age of Global Environment. As a result, a new 500kW WECS R&D project has started in FY1991 and the operation started in FY1996. A number of basic and applied studies have been undertaken at the NEDO, the MEL and many universities. Interests in utilization of wind energy have spread gradually among power company. From FY1991, the Tohoku Electric Power Company has operated a 2,875kW Windpark(5 units of 275kW machine and 5 units of 300kW machine) at Tappi, where the annual wind speed is as strong as 10m/s.Researches and demonstrations are also conducted by some other power companies. MHI has developed middle-sized commercial WTGs. More than 800 units were exported to the United States and UK. IHI also developed 300kW machines. Fuji Heavy Industry is developing new concept machine of small to medium size.

An Integrated Support System for Protective Relay Setting Designed to Enhance Function Linkage and Improve Data Reusability

The task of setting a protective relay requires various analytical calculations and coordination studies, and is thus complex and labor-intensive. While proposed conventional support systems are equipped with the required calculation functions, the systems are problematic with regard to practicability. Our newly developed system not only integrates all required calculation functions based on a user-friendly GUI, but also dramatically improves system practicability mainly owing to the following developments: · Functions which enhance the linkage between comprehensive calculation functions and the database · Functions which automatically set parameters and execute standard-desirable fault calculations · A relay-type-independent simulation method of protective relay sequence logic and a user maintenance function of the protective relay sequence databaseThis system presently performs network linkage operations in 22 locations of the Tohoku Electric Power Company, and has achieved great success in many respects with regard to the protective relay planning and operation, such as thorough relay operation analysis at the time of a power system fault.

Wind energy activities in Japan

This paper describes recent activities on wind energy in Japan. The national “Sunshine Project” conducted by the Ministry of International Trade and Industry, was reviewed in 1990 to map out a new energy strategy in the Age of Global Environment. As a result, a new 500kW WECS R&D project has started in FY1991 and the operation started in FY1996. A number of basic and applied studies have been undertaken at the NEDO, the MEL and many universities. Interests in utilization of wind energy have spread gradually among power company. From FY1991, the Tohoku Electric Power Company has operated a 2,875kW Windpark(5 units of 275kW machine and 5 units of 300kW machine) at Tappi, where the annual wind speed is as strong as 10m/s. Researches and demonstrations are also conducted by some other power companies. MHI has developed middle-sized commercial WTGs. More than 800 units were exported to the United States and UK. IHI also developed 300kW machines. Fuji Heavy Industry is developing new concept machine of small to medium size.

GPS Application for Synchronous Monitoring System at Multiple Location

Tohoku Electric Power Company and Tohoku University are cooperatively studying the effective use of a new monitoring .system using GPS (Global Positioning System). This system ensures achieving synchronous measurements at multiple remote electric supply station by using the time stamp facilities of GPS. First, this paper introduces briefly "Synchronous Monitoring System at multiple locations applying GPS techniques". Following section summarizes features of power flow fluctuation gotten by the developed monitoring system. The authors suggest some visual methodologies todisplay the features of the acquired data, and conduct a feasibility study on extracting hidden signals to identify insecure conditions in the power system.

Geothermal Energy: Clean and Reliable Energy for 21st Century. On the Geothermal Development by the Tohoku Electric Power Company, Inc.

Geothermal Energy: Clean and Reliable Energy for 21st Century. On the Geothermal Development by the Tohoku Electric Power Company, Inc.

Carbon dioxide fixation by microalgae photosynthesis using actual flue gas discharged from a boiler

To mitigate the effects of carbon dioxide discharged from a boiler in a power plant, CO2 fixation by microalgae photosynthesis was studied. For the algae cultivation, actual flue gas from a boiler was used in two sets of small-sized raceway-type cultivators installed at Tohoku Electric Power Company's Shin-Sendai power station. UsingNannochloropsis sp. NANNP-2 andPhaeodactylum sp. PHAEO-2 strains from the SERI collection, the microalgae were cultured semicontinuously and harvested periodically. From the results of the field test, the productivity of both strains using direct flue gas was almost on a par with that of bombed CO2 gas. Therefore, it was clarified that the direct blowing of flue gas into the cultivator did not adversely affect algal growth.

Development and implementation of a power system fault diagnosis expert system

This paper describes a fault diagnosis expert system installed at the Tohoku Electric Power Company. The main features of this system are careful selection of the inferencing input data, rapid inferencing, integration of the expert system with other systems in a practical structure, and the adoption of a domain shell. This system aims for improved practicability by using time-tagged data from circuit breakers, protective relays, and automatic reclosing relays in addition to the input data used in earlier systems. Furthermore, this system also uses data from fault detection systems that locate fault points within electric stations. This system uses an AI-specific back-end processor to perform inferencing rapidly. Additionally, this fault diagnosis expert system is interfaced and integrated with a restorative operations expert system, an intelligent alarm processing system, and a protective relay setting and management system. The authors developed and adopted a power system fault diagnosis domain shell to ease system development, and used the protective relay operation simulation function of a protective relay setting and management system for system verification. >

風力発電システムの運転特性シミュレーション-竜飛ウィンドパークにおける場合-

Tohoku Electric Power Company constructed a wind park composed of five 275kW windturbines (WT) at a cape TAPPI in AOMORI prefecture in 1991, and has begun an actual proof test from April 1992. A WT has a very unique point compared with other conventional electric power plants that the power of a WT is always fluctuating following the cube of wind speed and start-stop operation in very frequent. On the other hand, an induction generator is widely used for a WT, because it is very cost effective in manufacturing, maintenance and is very reliable. But the induction generator has a weak point producing high voltage fluctuation when connected into grid.Utility company has an obligation to keep voltage fluctuation within an allowable value, so we have to examine the performance of a WT previously. If there is any ploblem, we must take a suitable conter-measure. In order to evaluate the wind generator performance, simulation seems to be the best way. Hence, we made simulations on transient and normal characteristic of a WT, and found the simulation corresponded with the measured results very well.

Tappi wind-park of Tohoku electric power company

Tappi wind-park of Tohoku electric power company

An Advanced Integrated System for Electric Energy Supply Planning

Tohoku Electric Power Company has embarked on a company-wide long-range program for the introduction of a totally integrated computerized system for planning, operations and management with the objective of further sophisticated and enhanced business operations in the 21st Century. Research and development of the "Energy Supply Planning and Offical Intelligent Report System (ESPOIR)," which is the key to the realization of this broad vision, was started in 1983. The components of ESPOIR have been applied to the company's daily routine work as they were developed. As the result of this evolutionary development process, all fundamental subsystems were completed by 1988, and these subsystems have been integrated to realize a comprehensive electric energy supply planning system, namely, ESPOIR. The system has been successfully applied to power system planning and operations studies at the company. This paper describes the most advanced electric energy supply planning system of Tohoku Electric Power Company.

New Advanced Training Simulator Design for Power System Operations

In order to prevent human error, the importance of training and improving the skills of personnel involved in operations and maintenance can never be overly emphasized. First, this paper gives a brief overview of Tohoku Electric Power Company's new Training Center Scheme for 21st Century education strategies. Second, it explains the design concepts of an advanced training simulator for power system operators, which will be installed in the Center in 1990. Conventional simulators used at other electric utilities are capable of training personnel in frequency, load flow and voltage control. However, the most critical operations during periods of emergency and restoration of power supply are switchgear operations in which procedure operators must infer from protective relay information where the disturbance has occurred and how to restore trippcd-out transmission lines by separating disturbed lines or busbars. For this purpose, it is essential to have functions simulating the repercussions of fault phenomena activated by protective relays or breaker operations. This paper describes the most advanced technologies and innovations applied to the design of an epochal training simulator for power system operations.

On-Line Load Dispatching Control with Security Constraints at the Tohoku Electric Power Company

This paper presents an on-line load dispatching control system with security constraints which will start to operate in 1984 at the Tohoku Electric Power Company in Japan. One of these authors had developed a novel technique for an optimal power flow problem which was formulated based on the Decoupled Newton Load Flow method well recognized in bulk power systems. That is, the optimal power flow problem was formulated into P-0 active power and Q-V reactive power networks. Quadratic programming was employed to solve the OPF problem. The main algorithm of the developed system comprises the only P-0 active power network of the OPF problem. The system is able to minimize either generation costs or sum of squares of deviations between generator outputs and desired ones by controlling generators. The constraints consist of generator operating limitations and of power flow limitations which are restricted by thermal capacities or transient stability. If the problem has not a solution to satisfy the constraints, this system gives a solution which minimize sum of squares of the power flow violations. This on-line system is capable of dealing with a problem size of up to 180 buses, 200 lines, 26 controlling generators and 3 phase-shifting transformers.

On-Line Load Dispatching Control with Security Constraints at the Tohoku Electric Power Company

On-Line Load Dispatching Control with Security Constraints at the Tohoku Electric Power Company