Base Technology Subjects
System Engineering Research Laboratory
Brief Overview
The System Engineering Research Laboratory (SERL) conducts research on planning, operation, control
and analysis methods for electric power transmission, distribution systems as well as information and communication systems to facilitate secure supply of electricity generated by large-scale and distributed power sources.
The laboratory also pursues research on development, test and assessment of customer service technologies toachieve efﬁcient use of electricity.

Achievements by Research ThemeElectric Power Systems【Objectives】
We develop new electric power system control and monitoring technologies and protective relay settings
support systems, in order to secure power systems from potential stability deterioration and protection coordination failures that would be caused by high penetration of renewable energy resources in the near future.
【Principal Results】
・It is necessary to evaluate the inﬂuence of high penetration of renewable energy on transient phenomena in caseof a line fault in a transmission system. Therefore, we installed PCSs (Power Conditioners) for PVs, DC power
supply that emulates photovoltaic cells, and other equipment into CRIEPIʼs Power System Simulator (Fig. 1).
The reinforcement will be completed in September, 2010.
・We have developed a checking system of protection coordination between earth fault relays for ungroundedsystems and integrated it into the Support System for Setting and Coordination (SSSC). This enables us tojudge the validity of coordination between earth-fault-relays in addition to that between short-circuit-relays.
[R09007].
Customer Systems【Objectives】
In order to accelerate energy conservation, we assemble a database on energy demand and develop a supporting tool for energy-saving. We also aim to put a watching system for elderly single persons into practical use.
【Principal Results】
・We developed a method converting original data into imaginary ones in order to assemble a data base onenergy demand protecting purveyor privacy [R09021].
・We developed a comprehensive evaluation technique based on Data Enveloped Analysis. It enables us to
examine energy efﬁciency of customers taking into consideration energy-saving, environmental, and economical aspects simultaneously [R09006].
・We developed a prototype watching system for elderly single persons and carried out a one-year demonstration
test on 11 elderly single persons in the City of Komae in Tokyo. We veriﬁed the effectiveness of the systemthrough the test [R09014].
Communication Systems【Objectives】
As fundamental technologies of future communication network for power utilities, we will develop disas82

System Engineering Research Laboratory
ter countermeasure technologies, communication media technologies for facility maintenance work, security
technologies for the SCADA system and others.
【Principal Results】
・We proposed a simple and fast method to compensate the distortion of optical ﬁber communication signal(wavelength dispersion) which occurs on switching ﬁber in a high speed network due to a disaster and demonstrated that the compensation can be operated within one second [R09018].
・In order to install sensors at the place such as around power transmission lines where it is difﬁcult to supply thepower for driving sensors, we proposed a multi-point and high-function optical sensor system which provides
the optical power for driving optical nodes and acquires many types and a number of sensor data through thecomposite of optical ﬁbers and switches (Fig. 2) [R09004].
Mathematical Informatics【Objectives】
To assess the risk of information security, we will develop an Information Technology (IT) risk guideline
for a large-scale information system. And to monitor the condition of equipment, we will develop an image measurement method and a monitoring method based on image processing.
【Principal Results】
・We developed IT risk guidelines for a large-scale information system. The guidelines support the risk assessment and development of action plan for countermeasures. The guidelines divide the large-scale information
system into zones where the IT risk can be evaluated independently [R09019].
・We developed a detection method of abnormal parts of ground wire, such as wire cuts and ghost marks. The
developed a method using high resolution images and achieved high accuracy of detection, which can greatly
reduce the image conﬁrmation work time of people [R09016].

Fig.1 Overview of power system simulator with renewable energy resources
Concentration center
Light sourcefor power supply

λP
OSW

λP
λS

λS (Return light)#1#2

Transmitter
Receiverfor OSW controland sensor signal#3
Optical sensor(reflection type)

λS

OSW

Optical fiber(trunk line)

WDM coupler
Light forpower supply λP
OSWStorage

Drivercircuit

O/E

λS

Return light
Incident light

1:1

Opticalsensor

Power supply

Optical switch (OSW)

Optical node(a) System overview(b) Optical nodeFig. 2 Conﬁguration of multiple optical sensor system using optical switch (OSW) and optical power supply
Lights for sensing and power supply are simultaneously transmitted via optical ﬁber, and distributed to an arbitrary node by
optical switching.

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