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To meet the growing public concern for the enhancement of reliability in supplying electricity and global environmental considerations, there is an increasing requirement for a high-quality power sector infrastructure in the field of generation, transmission and distribution. In line with such global interests, TEPCO has participated in consulting services of electric facilities overseas, utilizing our expertise and know-how accumulated from our experience in Japan. TEPCO can propose improvement of power supply reliability, assist power sector development and tackle global environmental problems, etc., in accordance with your requirements.

For more information, there is an exclusive website for overseas consultancy. Please click here.

Training Courses
Substation Automation
Protection Relay

Protection Relay

IntoroductionThe history of electric power system has been originated in 1900s in Japan. Then, to cope with following demand growth, high voltage and bulk power transmission technology has been developed. In 1973, 500kV bulk power transmission system has been put into operation. To compose such a huge and complication power system, much more rapidity, higher reliability and performance of protective relay system was expected. Thus, electromagnetic relays and static relays were developed and numerical relays equipped with computer are adopted currently.
The fundamental training course and application training course (five days for each course) are available for the engineer who needs the engineering and experiences accumulated by TEPCO through its history in the field of protection relays. TEPCO believes that the course would be really useful for the engineers of utilities, especially for the system planner of the relay systems of substations and transmission/distribution lines.

Outline of the Course (fundamental/application)
The major contents of fundamental course are the protection schemes in distribution substations and application course's are the schemes in transmission substations. Both courses are consist of five days. TEPCO can process its substantial experiences into the useful information by the same point of view with the attendants as "Engineer of Utility". It is so helpful in order to find out the most suitable system for your company.

Main Subjects are as follows:
  1. Outline of Transmission Network and Substation Facilities in TEPCO
  2. Outline of Relay System for Distribution Substations and Distribution Lines (fundamental course)
  3. Outline of Relay System for Transmission Substations and Transmission Lines (application course)
  4. Specification, Structure, Operation and Maintenance
  5. Technical Tour for Control Centers or Distribution Substations

The lectures are performed not only in classroom, but also in TEPCO's Training Center using real scale simulator. The course includes the technical tour to the substations and other facilities to make attendants understand the philosophy, real situations and subjects in the field.

In addition, attendants will be kindly expected to perform small presentation about their system or future plans. Based on this presentation, attendants and TEPCO experts has a chance to discuss over the subjects and experts will make some suggestions.

Courses Relays Automatic Restoration Options
Fundamental Relays mainly applied to distribution substations and its source lines in 66kV and below Over Current Relay
Over Current Grounding Relay
Directional Grounding Relay
Rational Differencial Relay
Distance Relay
Automatic Restorative
Sequencial Controller *1

Distribution Line Fault
Detector &Automatic
Re-closing Scheme *2
Discussion on the protection scheme in attendants' company

  • ground fault current setting in the system whose neutral point is grounded via resistor and application to attendants' system
  • study on attendants' system improvement of relay schemes and coordination in order to minimize the outage area
Application Relays mainly applied to transmission substations and its source lines beyond 66kV Distance Reley
Transverse Differncial Relay
Current Differencial Relay
Bus isolation Relay
Bus Protection Relay
Automatic Bus-Tie Closer
Automatic Re-closing
Scheme (high speed, multi
phase re-closing) *3

*1 Automatic restoration controller applied for fault on source transmission lines or
*2 Automatic controller to isolate faulted section of distribution lines and to restore
     sound sections, applied by the combination with automatic re-closer
*3 Automatic controller restoring outage and overload by closing bus tie CB, in case of
     that transformer fault results in bus outage or overload of remaining sound transformers
Course Example
1. Outline of Power System Network and Substation Facilities in TEPCO (Half day)
Lectures to understand the purpose of configuration and arrangement of TEPCO system, in order to point out the difference between attendant's company and TEPCO and form the background of the study
  • Configuration and history of TEPCO power network
  • Equipment arrangement and configuration of Distribution Substations

2. Outline of the Relay Schemes in Distribution Substation and Distribution Line
    (Fundamental course), or Transmission Substations and Transmission Lines
    (Application course) (2.5 days for each course)
TEPCO's philosophy is represented to be understand as a reference to design attendant's concept of relay system.
  • Typical relay schemes (Fundamental course; power source line protection, transformer protection, distribution line protection: Application course; line protection, transformer protection, bus protection )
  • Basis of selecting appropriate scheme and subjects to be considered
  • Automatic re-closing of distribution lines
  • History of relay equipment (electromagnetic type, static type, numerical type)
  • Relay setting (coordination, timer, and inverse time-lag schemes)
  • Maintenance, inspection, testing method

3. Specification, Mechanism and O&M of Relays (One day)
TEPCO's training center Lectures to understand specification, mechanism and O&M of relays using full-scaled model of relays of distribution lines or distribution substations at TEPCO technical training center.
  • Standard specification and mechanism of relays in distribution substations and distribution lines
  • Maintenance and testing methods of relays (including practice of testing methods)

4. Technical Tour to the Field (One day)
Technical tour to the distribution substations and control centers in order to understand the situation of real facilities

*Based on the presentation performed by attendants, discussion with experts will be arranged and TEPCO experts shall make some useful suggestions

Technical Tour to the Field

5. Technical Tour for Control Centers and Distribution Substations (Two days)
Tours for control centers, distribution substations and relay stations to confirm the real facilities and environment in the field.
According to the presentation provided by the attendants, discussion with TEPCO experts will be ready on the last day. TEPCO experts may prepare some recommendations.
Course Instruction Details
For further information regarding the details of the course, please contact us.

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