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Diagnosis

  • Energized
  • Deenergized

Electrical faults

  • overload
  • earth leakage faults
  • open circuits
  • short circuits
  • high resistance joints
  • incomplete ring-circuits
  • oversensitive/non-performing RCDs.

Electrical systems

  • ELV and LV single and multiphase
  • power
  • lighting
  • controls.

Diagnosis of AC Insulation

Introduction

Diagnose aging condition of insulator by estimating dielectric loss resulted from void, stain and molsture absorption with injecting applied-voltage to objects

Characteristics

Current Transformer Tester

Diagnosis Object

Transformer, Cable, Motor, GIS Facility

Expected Effect

Diagnosis of aging condition, Anticipation of expected life

Example

  • As a result of cable's AC insulation diagnosis, the occurrence of excessive insulation loss
  • As a result of inc ising straight conjunction point, the detection of the carbonization steeply developing to a grounding fau lt
Diagnosis of AC Insulation
PhaseApplied voltage[kV]Diagnosis resultDecision
Loss[W]tanδ[%]
R 1.0 183.69 1.23 bad
1.5 136.36 0.91
2.0 113.31 0.76
S 1.0 48.149 0.32 good
1.5 45.851 0.31
2.0 44.239 0.30
T 1.0 52.365 0.36 good
1.5 46.949 0.32
2.0 42.866 0.29
Current Transformer Tester

Diagnosis of Circuit Breaker

Introduction

Preventing major fault factor in advance and improving breaking performance and reliability through Circuit Breaker's performance characteristics diagnosis, partial abrasion condition

Introduction

Characterstics

  • Measuring the degree of Circuit Breaker's vacuum condition
  • Diagnosing condition of Circuit Breaker's abrasion
  • Analyzing the characteristics of Circuit Breaker's performance
    • Circuit Breaker's Open-Close Time DOUBLE Characteristics
    • Diagnosis the occurrence of chattering phenomenon, asynchronous open-close, etc
Characterstics

Analysis of repairing, replacing, cleaning Abrasion Part and it's mechanism

  • Insulation Frame Assy's Condition Diagnosis and Cleaning
  • Main Contact Assy's Condition Diagnosis and Cleaning
  • Contact Shunt Assy's Condition Diagnosis and Cleaning
  • Insulation Barrier
    • Absorption, Smudge, Arc Point Condition Diagnosis and Cleaning
  • Insulator
    • Smuge, Damage, Insulation Maintenance Condition Diagnosis
  • Vacuum Bulb Assy's
    • Checking Damage of Bulb, Transformation and Condition Diagnosis
Analysis of repairing, replacing, cleaning Abrasion Part and it's mechanism

Diagnosis Object

VCB, VCS, ACN etc.

Diagnosis Object

Expected Effect

Improving breaking performance and reliability of circu breaker

Expected Effect

Diagnosis of Current Transformer

Introduction

Testing characteristics of saturation voltage and errors of current transformer in its over -current area

Characteristics

Analyzing Ratio, Phase, Polarity Saturation characteristic, Resistance, Burden etc

Current Transformer Tester

Diagnosis Object

Current Transformer

Expected Effect

  • Assuring smooth perfo rmance of protection relay in the event of fault current
  • Checking cha racterist ics of current transformer

Example

Checking abnormal saturation voltage while testing saturation characteristics of current transformer

Example
No. Rated Decision
PhaseRatioOvercurrent integerBurden(VA)Saturation voltageRatio errorOvercurrent integerPolarity
1 R 100/5 10 40 N/A 0.21 0.0 depolarity bad
2 S 100/5 10 40 76.0 0.41 9.5 depolarity good
3 T 100/5 10 40 78.0 0.41 9.8 depolarity good
Current Transformer Tester

Diagnosis of Partial Discharge

Introduction

Diagnosing aging conditio n by detecting and analyzing a partial discharge signal at electrical facilities in motion

Analysis of partial discharge

Characteristics

  • Detecing a partial discharge signal by analyzing characteristic of pulse signal
  • Finding the cause of a partial discharge by using inductive, conductive and ultrasonic sensor
  • Making it easier to build DB and manage trend

Diagnosis Object

Extra-hight voltage facilities such as transfomer, cable, motor etc.

Expected Effect

Prevention of serious accidents by detecting early aging phenomenon

Example

Occurrence of partial discharge of cable and transfomer.
※In case of transfo rmers, judged as inner electric discharge as result of t he gas analysis of insulating oil

ObjectDataActual pictureResult
Cable Cable PD
(Void)
Tr TrPD
(Corna)

Test Equipment

Test Equipment

Diagnosis of UHF for GIS

Introduction

As a method of detecing electromagnetic wave, detecting inner partial discharge by attaching a belt-shaped sensor that detects UHF bandwidth to a part of GIS spacer

Characteristics

  • Analysing frequency components reaching up to GHz
  • Diagnosing three-phase separation typed GIS at a time
  • Making it easier to build DB and manage trend.
GIS UHF TesterDMSI

Diagnosis Object

GIS

Expected Effect

  • Finding the pnt & frequency of occurrence regarding insulation aging and progress taking place at GIS
  • Making it easy to find early breakdown when GIS is under on-line-condition
  • Minimizing damage by preventing electric accidents in advance

Example

Attachment of UHF sensor and analysis of insulation condition

Attachment 01 UHF sensor, Measurement data

Water-Tree Diagnosis for XLPE Cable

Introduction

Diagnosis of Water - Tree

Characteristics

Checking abnormality of cable by analyzibng Water- Tree phenomenon is the main cause for power cable insulating aging

Method of testing, Online Cable(Water Tree)Tester

Diagnosis Object

Hight voltage cables [3.3kV, 6.6kV etcJ]

Expected Effect

  • Managing the trend of the degree to which Water- Tree of cable insulator progreses
  • Deciding cable aging

Example

  • Test resu it's "C". because DC Component average and the range of fluchuation are more than 100mA
  • As a result of cable inspection, sture pemeated t he motor junction box
ObjectCable
Standard
[1㎟]
Length
[1m]
Actual pictureSeath Insulation
Resistance
[㏁]
Judgement
MaxMinAvg
Junction box 1/3Cx80 60m 3,200 2,800 2,960 666 C

Disjuncture of Junction box

Diagnosis of Ultraviolet Rays Corana

introduction

Detecting phenomenon such as corona, arc and partial discharge that generated in extra-high voltage facilities on hot-line

Characteristics

    • Measurement regardless of the effect of solar radition
    • Making it easier to build DB and manage trend

Diagnosis Object

        • Power transmission : Connector, Overhead transmission lines etc
        • Substation : Insulator, Switch-gear, Bushing, Connector, Transformer etc
        • Distribution : Connector, Switch-gear, Insulator etc
        • High voltage motor : Inspectiong corona of co il[ln case of dismantling]

Expected Effect

            • Early detection of overheat, overload, contact failure
            • Communication noise and audio noise can be removed

Example

Detecting corona from insulator at the bottom of MOF

Diagnosis of Onfrared Thermography

Introduction

Diagnosing abnormal generated heat position and aging condition by displaying image of temperature distribution that occurs from electrical facilities on hot-line

Characteristics

  • Taking and saving both actual picture and infra red rays image of diagnosis object at the same
  • Making it easier to build DB and manage trend

Diagnosis Object

  • Power transmission : Overhead transmission lines etc
  • Substation : insulator, switch-gear, bushing, connector, transformer etc
  • Distribution of electricity : connector on the concrete electric pole, switch-gear, insu lator etc

Expected Effect

Early detection of overheat, overload, contact fa ilure

Example

  • Unsuitable tray wiring of high-voltage cable
  • Occurrence of overheat of cable & tray due to cable's eddy current

Radiation Transmittance Diagnosis

Introduction

Checking inner connection and assembly status of GIS by using ratiation permeation and absorption of radiation property in material

Characteristics

  • Quality about an inner condition and detection of structural defeats.
  • Determine the form. size and distribut ion of structural defects
  • Accommodate semi-permanently storage of diagnosis datalrecord filemsi.
  • Securing safety in accordance with handling of rad iat ion.

Diagnosis Object

Extra-High Voltage Cables, GIS facilities etc

Expected Effect

Detecting the intemal structure for defects in online.

Example

  • Checking a partial disposition of the inner conductor of GIS
  • Confirming the torsional occurrence of tulip segment(Connection between the conductor)