General Overview

Advanced Maintenance Technology− Rational Operation of Electric Facilities−
Brief Overview
To contribute to total cost reduction and ensuring reliability on electric facility arrangement to maintenance technology frompower generation to transmission and distribution, we developed facility diagnostic technology and operation maintenance supporting
technology applying at the power business site immediately.
For power generating facilities, we applied internal pressure bending creep tests for full-scale piping weld specimen to
establish life assessment method of aged power generating components and steel structures through crack detection closely related to
the life and clarified changes in failed conditions at the weld heat affected zones after 3,000 hours long period operation.
For transmission and distribution facilities, aiming at construction of maintenance standard for aged facilities we developed
the component deterioration diagnostic technology to verify that abnormal phenomena such as partial discharge and conductor contact
failure expected at aged gas-insulated switchgear (GIS) can be detected by using accumulation of SF6 decomposite gas.

Achievements by Research Theme
Advanced maintenance technology of power generating facilities● Gas turbine hot gas path parts maintenance・ Practical operation of the X ray CT scanning system has been started, and the system was applied to the measurement of usedparts.
・ Improvement in reliability of operating temperature distribution estimates has been made for film-cooled and TBC-coated blades.
*TBC; thermal barrier coating.
○ Power generating plant performance diagnostics
・ We promoted to distribute diagnostics method to power plants by establishing support system of the thermal efficiency analysis
program for power generation systems and by enhancing function to increase convenience to program users.
● Status diagnostics on power generation components
・ We developed high-speed simulation program for ultrasonic flaw detection to shorten the current prediction time for ultrasonicpropagation behavior nearly to 1/10. (Fig.1 Table1)
・ We conducted internal pressure bending creep test for full-sized piping weld specimen to determine changes in failed conditionof weld heat affected zone due to long time operation (after 3,000 hours).
Advanced maintenance technology of power distribution facilities● Establishment of maintenance standards for aged electric facilities
・ We verified that abnormal phenomenon of aged gas-insulated switchgear (GIS) was be able to detect applying accumulated
decomposite gas of SF6.
・ We verified diagnostics method possible for detection of water tree degradation and location causing aged deterioration ofXLPE power cables.
○Management measures for power distribution facilities
・We developed fundamental model assessing the effect of power transmitting congestion mitigation and avoidance of supplying
troubles.
○Asset management of power network
・We were developing a support tool to level transmission equipment replacements over long planning horizon. Essential parts
including reliability assessment and procedures to develop replacement plan were implemented.
○Asset management support technology
・ Maintenance management plan support tools developed by CRIEPI were remodeled to a general-purpose model to apply tovarious power components with different performance in aged deterioration. (Fig.2)

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Advanced maintenance technology

Advanced maintenance technologies for electric power facilities
ProbeASpecimen

W in：Waves into small region
W out：Waves out of small regionW inGet W in by analytical solution

W out

Small region whereFEM is applied

Calculate W out with FEM

Boundaries of small region

Obtain received signals by
the reciprocity theorem withW in, W out and incident pulse

Crack

Region with absorbing boundary
condition (external region)

Fig.1 Development of hybrid method for high speed simulation of wave propagation
based on the combination of analytical solution and the finite element method
Table 1 In comparison with traditional FEM, computation time by developed method
decreases to one tenth and results are almost the same
Probe positionOpening

12.7mmFlexion

A

True depth

Branches

Inspection images (numerical prediction)
Probe position
A:Echo from branches
B:Echo from flexion
C:Echo fromopening

A

True depth

Photo of specimenTip

B

Developed method C

Traditional FEM

ABCAdvanced maintenance technology of power distribution facilities

Concept of PD source location with Oscillating
Wave High Voltage Testing Method

Conceptual output of asset management support tool ofnetwork construction in competitive circumstances

Conceptual output of Network AssetManagement Support tool

Display of support program for overhaul planning (Costsare normalized by an install cost of an equipment)

Fig.2 New Diagnostic Method and Asset Management Decision Support Tools

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