PRESERVING & MAINTAINING

A GUIDE TO BEST PRACTICE

PRESERVING &MAINTAININGYOUR ELECTRICAL EQUIPMENT

OBJECTIVESOF THE EXCELEC GUIDE

This professional guide is aimed at aiding the maintenance manager

of an electrical installation, as well as the buyers of these services, to optimise

maintenance in terms of both costs and quality.

It provides a tool for optimal implementation of maintenance services taking

into account the potential risks and industry know-how.

Focused on the entire life cycle of the equipment, the Excelec Guide describes a large

range of operations aimed at checking and preserving the life of an electrical

installation, and establishing the level of complexity of each maintenance operation.

The Guide also recommends the optimal frequency of the various operations,

adapted to the corresponding phase of the equipment life cycle, to anticipate specific

needs and allow overall cost optimisation.

This Excelec Guide is, above all, an aid for a dialogue between the maintenance

provider and the client, intended to clarify the discussion and to establish basic

reflexes concerning maintenance.

It also allows the client to build up a maintenance plan and to take advantage of

regular servicing operations by a maintenance specialist to assess his installation.

Thanks to the product knowledge and long-term vision of the maintenance

specialist, the client can also get advice on how to develop or update his investment

plan, based on expert recommendations, and thereby be able to control

his overall operating costs.

The maintenance specialist, based on his know-how and perfect familiarity

with the equipment, is able to offer the appropriate operation corresponding to

the life-cycle stage of the equipment, and can give guidance on optimised maintenance

management, which can extend the equipment’s useful life.

INSTALL

OPERATE

VERIFY

MAINTAIN

FIVE EXCELECLEVELS

LEVELRoutine maintenance

Maintenance operations are generally described in the maintenance guide

given by the manufacturer.

For example: adjustment, level checks, replacement of consumable parts.

LEVELActions requiring simple procedures and/or support equipment (integrated

into the equipment or outside it) simple to use or to implement.



For example: Replacement/exchange of components, simple inspections.

LEVELOperations requiring complex procedures and/or support equipment which

are either complex to use or to implement.

For example: replacement of manufacturer's original parts, complex

adjustments, realignment.

LEVELOperations involving procedures which imply the mastery of a particular

technique or technology and/or the implementation of specialized support

equipment.

For example: Technical upgrading, change of function performance,

change of use.

LEVELOperations involving procedures which imply expertise, requiring particular

techniques or technologies, processes and/or industrial support equipment.

For example: general overhaul with complete dismantling of equipment,

replacement of obsolete or worn-out equipment.

5

4

3

2

1

NB: Extracts from Afnor Standard FDX 60-000, Industrial Maintenance, dated May 2002. Determination of maintenance levels.

EXCELEC DATA SHEETS

PRESERVING & MAINTAINING YOUR ELECTRICAL EQUIPMENT

TECHNICAL DATA SHEETSJuly 2007

Low voltage power distribution schwitchboards and motor control centres

Monitoring and measurement equipment

Protection relays

Cubicle with circuit breaker and MV associated protection

MV Circuit-breaker operating mechanisms

MV circuit switch cubicle

Distribution transformer

Minimum oil circuit breakers

SF6 Circuit breakers

Circuit-breaker operating mechanisms

Disconnectors

Surge arrestors, CTs, VTs

GIS equipment

Power transformer

LV : Low Voltage

MV : Medium Voltage

HV : High Voltage

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EXCELEC DATA SHEETS


* in normal operating conditions

LOW VOLTAGE POWER DISTRIBUTION SCHWITCHBOARDS

AND MOTOR CONTROL CENTRES

LV

EQUIPMENT DESCRIPTION RECOMMENDED EXCELEC

OF THE OPERATION FREQUENCY* LEVEL

Electrical room: In case of switchboard 2- Levelness of support/Alignment extension

Upgrade: According to upgrade

- Extension according

to TTA/PTTA

definition 4- Updating of software According to manufacturer’s

instructions

Indications:

- Check on indicators Every month 1(indicator lights, mechanical

indicators, etc...)

- Check on values indicated Every two years 2by measuring equipment

Enclosure:

- Efficiency and presence Every year

of interlocking devices

- Cover panel and partition Every year

(doors, form covers, automatic 1shutters, screws, keys, etc...)

- General appearance: cleanliness, Every year

presence of humidity,

oxidation

- Strain Every year

- Dedusting of switchboard Every year

LOW VOLTAGE SWITCHBOARDS

LOW VOLTAGE POWER DISTRIBUTION SCHWITCHBOARDS

AND MOTOR CONTROL CENTRES



Connections:

- Heating Every year 3

- Power connection According 3checks (busbars, to manufacturer’s

terminations and busbar instruction

supports)

- Downstream power connection Every year 3checks (connecting pads,

cable mechanical strength)

- Earth connection checks Every year 3

- Clamp connection checks Every year 3(wear and greasing)

- Auxiliary connection checks Every year 2

Switchgear and controlgear:

- Dedusting Every year 1

- Protection setting according During commissioning 2to discrimination study

- Check on switchgear Every 3 years 3wearing parts

(main contacts,

arcing chamber)

- Opening/closing checks Every year 1

Electrical environment:

- Harmonic content checks Depending on changes 1in downstream loads

LOW VOLTAGE SWITCHBOARDS


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LV

MONITORING AND MEASUREMENT EQUIPMENTDigital Control Systems, Remote Terminal Units, Event Recorders,

Fault Recorders, Transducers, Meters



Fan filter replacement Every year 2

Fan/drive system Every year 2rack checking

Computer fan checking Every year 2

Power supply checking Every year 2(noise level)

Event log analysis Every year 2and checking

Connection checking Every year 2

Cabling check Every year 2

Battery check / replacement Every 5 years 2(CPU, SRAM)

Checking and tightness of test Every 5 years 2and connection units

Electronic components Every 10 years 5aging study (where applicable)

Electrical network setting On any electrical 5checking and modification network change

Software upgrade According to manufacturer’s 4instructions

Hardware upgrade On change request 4

MONITORING AND

MEASUREMENT EQUIPMENT

EXCELEC DATA SHEETS



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MV/LV

PROTECTION RELAYSDistance, line differential, Busbar, feeders, motors, generators



Connexion check Every year 2

Cabling check Every year 2

Secondary injection testing Every year to

Backup battery Every 5 years 2checking / replacement

(digital relays)

Checking and tightness Every 5 years 2of test and connection

units

Electronic components Every 10 years 5aging study

(analogue relays)

Electrical network settings, Upon any electrical 5checking and modification network change

Software upgrade According to manufacturer’s 4(digital relays) instructions

Equipment upgrade On change request or 4according to manufacturer’s

instructions

43

PROTECTION RELAYS

(according to type

of protection)

EXCELEC DATA SHEETS



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MV

OIL CIRCUIT BREAKERS



General state visual checking, Every year, energized 1cleanliness, insulator condition,

oxidation, no corrosion

of supporting structure, etc.

Reading operating counter Every year 1

Tightness checking of: Every year, 2- Screws of supporting structure - energized

- High Voltage (HV) connections - de-energized

Check on general state and absence Every year, energized 2of traces of overheating

on earthing connections

Oil level checks; Every year, energized 2Tightness testing

Check on operating times Every 3 years, de-energized 3and synchronization

Insulator cleaning Every 3 years, 2energized or de-energized

Measurement of dielectric losses Every 3 years, de-energized 4(poles, dielectric oil, insulating

transmission oil if necessary)

Measurement of main Every 3 years, de-energized 4contact resistance

Replacement of dielectric oil Every 5 years, de-energized 2

Wear checks on arcing contacts Every 5 years, 4depending on use

Renovation and upgrading Every 20 years 4

CIRCUIT BREAKERS

EXCELEC DATA SHEETS



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MV

SF6 CIRCUIT BREAKERS




oxidation, no corrosion

of supporting structure, etc...


Tightness checking of: Every year, 2- Screws of supporting structure - energized

- High Voltage (HV) connections - de-energized

Checking of overall condition Every year, energized 2and earthing connections

(no sign of overheating)

SF6 pressure Every 3 years 2checking

Cleaning of insulators Every 3 years, 2(Particular risk: energized or de-energized

under-pressure insulators)

Check on Every 3 years, de-energized 4operating times and

synchronization

Checking of Every 5 years, de-energized 4density meter operation

and gas quality

Resistance measurement Every 5 years, de-energized 4on main contacts

Replacement of capacitors Every 5000 operations 5or 25 years

de-energized

Renovation and upgrading Every 20 years 5

CIRCUIT BREAKERS

EXCELEC DATA SHEETS



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MV

CIRCUIT-BREAKER OPERATING MECHANISMS




Checking of Low Voltage terminals Every 5 years 2and Low Voltage connections

Checking of the oil level Every year, energized 1and the absence of leakages

Reading of pump counter

Visual checking Every year 1of electrical equipment

and safety devices

Checking of hydraulic Every 40 months 2safety devices as per regulation

(valves, discharge valves)

Checking of pressure switch thresholds Every 5 years, energized 2and local/remote indicators

Oil filter replacement Every 5 years 2

Cleaning of tanks and circuits, Every 10 years, 3oil replacement de-energized

Accumulator replacement Every 10 years 4and/or requalification

Change of flexible pipes Every 15 years 4and check on connections

Upgrading and/or replacement Every 15 years 5of control units, cylinders,

hydraulic pumps

ALL MECHANISMS

HYDRAULIC MECHANISMS

EXCELEC DATA SHEETS



HV

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DISCONNECTORS




oxidation, no mounting corrosion, etc...

Check on overall condition and Every year, energized 2earthing connections

(no sign of overheating)

Tightness checking on: Every year, 2- Screws of supporting structure - energized

- HV connections - de-energized

Check on operating mechanism; Every year 1check on low voltage

components

Complete operating cycle Every year, de-energized 1for each equipment

Infrared thermography Every year, energized 3

Check on safety devices Every year 2(locking, indications)

Wiring state, tightening of Every 3 years 1terminal blocks, checking of heating

resistor and indications

Cleaning and checking of post insulators, Every 3 years, de-energized 2greasing of moving components

and connecting rod assemblies

Check on operating Every 3 years 3parameters and

mechanical torque

Measurement of Every 3 years 3main contact wear

Repair and/or replacement of wearing Every 15 years, 4parts (elastomer thrust stops, depending on

joint pins, plastic bearings, conditions of use

propulsion, etc.)

DISCONNECTORS

EXCELEC DATA SHEETS



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HV

SURGE ARRESTORS, CTS, VTS



Visual check: general appearance, Every year, energized 1cleanliness, cracks, corrosion

on supports, etc...

Insulator cleaning Every 3 years, energized 2or de-energized

Tightening checks: Every year 2support structure bolts, HV and energized

LV circuit connections de-energized

IR thermographic checks Every year, energized 3

Reading of discharge counters Every year 1

Earthing connection check Every year 1

Leak current check Every 3 years 4

Oil level check and leakage Every year 1identification and pinpointing

Oil sampling for analysis Every 5 years, de-energized 1

Secondary loads & load Every 5 years 3factor measurement

SF6 pressure check, Every year, energized 2leakage pinpointing and tapping-off

Secondary loads & load Every 5 years 3factor measurement

ALL

SURGE

ARRESTOR

OIL INSULATED CT’S

AND VT’S

SF6 INSULATED CT’S AND VT’S

EXCELEC DATA SHEETS



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HV

CUBICLE WITH CIRCUIT BREAKER AND

MV ASSOCIATED PROTECTION



Cleaning of cubicle and internal Every 3 years, de-energized 1equipment (voltage and

current transformers)

Checking of busbar connections, Every 3 years, de-energized 2tightening according to value

recommended by manufacturer

Cleaning and greasing Every 3 years, de-energized 2of earthing switch

Checking of earthing Every 3 years, de-energized 3switch mechanism

Opening and closing Every year if possible, 1of earthing switch or every 3 years

Checking of voltage and Every 3 years, de-energized 4current transformers

(overheating marks, cracks, etc...)

Checking of withdrawal Every 3 years, de-energized 3mechanism and shutters

Checking of locking Every 3 years, de-energized 3mechanism function

Checking of the position indicators Every year, energized 1and signalling switches

AIR INSULATED

MV CUBICLE

EXCELEC DATA SHEETS



MV

CUBICLE WITH CIRCUIT BREAKER AND

MV ASSOCIATED PROTECTION



Checking of opening and closing times, After 10 years or 4contact synchronization, closing 10 000 operations

and tripping speed, measuring whichever occurs the earlier,

of contact resistance then every 3 years

Checking, cleaning and greasing Every 3 years, de-energized 2of fixed and moving contacts

of withdrawable parts

Checking of the components Every 3 years 4in the latching mechanism,

replacement if necessary

Visual inspection of mechanism Every year 1and electrical equipment,

and safety devices

Visual checking Every year 1of external coupling rods

Cleaning and greasing Every 5 years 3

Replacement of wearing parts Every 5 years 3

Equipment opening Every year, de-energized 1and closing cycle

Checking of protection relay Every year, de-energized 4

Checking of upstream Every year, de-energized 4and downstream selectivity

CIRCUIT BREAKER

ASSOCIATED PROTECTION


MV

MV CIRCUIT-BREAKER OPERATING MECHANISMS



Visual examination of mechanism, Every year 1electrical equipment and

safety devices

Visual examination Every year 1of external coupling rods

Cleaning and greasing Every 3 or 5 years to

Replacement Every 3 or 5 years to

of wearing parts and

check on latching

Replacement of motor After 10 000 operations 4

Replacement of operation After 10 000 operations 4counter

Replacement of closing After 10 000 operations 4and tripping springs

Check on fastening of nuts Every 3 years 2and bolts and presence

of safety devices

43

43

MV CIRCUIT-BREAKER

MECHANISMS

* in normal operating conditions** according to the type of circuit-breaker

EXCELEC DATA SHEETS


MV

**

**

MV CIRCUIT SWITCH CUBICLE



Visual examination and cleaning Every year 1

Cleaning and greasing Every 3 years, de-energized 2of main contacts

Check on active part and Every 3 years, de-energized 2resin enclosures (overheating marks,

cracks, dust, etc...)

Visual inspection Every 3 years, de-energized 3of busbars and tightening

Check on the absence Every 3 years, de-energized 2of corona traces

on the MV cable ends

Removal, cleaning Every 3 years, de-energized 4and greasing of mechanism

Cleaning and greasing Every 3 years, de-energized 3of earthing switch where applicable

Check on earthing Every year if possible 2switch mechanism or every 3 years

Check on MV fuses Every 5 years, de-energized 4and comparison

with manufacturer's data

Check on system Every 3 years, de-energized 3for tripping by MV fuses

Mechanical test (closing, tripping, Every 3 years, de-energized 4locking mechanism)

Electrical and operating tests Every year, energized 3

Check on auxiliary contacts Every year, energized 2and position indicators


MV

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EXCELEC DATA SHEETS


A GUIDE TO BEST PRACTICE


23 rue Galilée - 75116 PARIS | Tél/Fax +33 (0)1 40 70 07 [email protected] | www.gimelec-promotion.fr ©

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LEVELRoutine maintenance



For example: adjustment, level checks, replacement of consumable parts.

LEVELActions requiring simple procedures and/or support equipment (integrated

into the equipment or outside it) simple to use or to implement.



For example: Replacement/exchange of components, simple inspections.

LEVELOperations requiring complex procedures and/or support equipment which

are either complex to use or to implement.

For example: replacement of manufacturer's original parts, complex

adjustments, realignment.

LEVELOperations involving procedures which imply the mastery of a particular

technique or technology and/or the implementation of specialized support

equipment.

For example: Technical upgrading, change of function performance,

change of use.

LEVELOperations involving procedures which imply expertise, requiring particular

techniques or technologies, processes and/or industrial support equipment.

For example: general overhaul with complete dismantling of equipment,

replacement of obsolete or worn-out equipment.

5

4

3

2

1

NB: Extracts from Afnor Standard FDX 60-000, Industrial Maintenance, dated May 2002. Determination of maintenance levels.

DISTRIBUTION TRANSFORMER



Commissioning of transformers: At commissioning

- Preparation for shipment 1

- Shipment – Unloading 1

- Erection – Installation 3

- Other operations 4(oil filling)

- Checks (protection systems, 3automatic controls)

- Commissioning 4

Repair/refurbishment in factory: During repair/

- On-site diagnosis refurbishment in factory 5


- Shipment - Unloading 1

- Untanking 4

- Expert appraisal 4

- Active part dismantling 5

- Calculation and design 4

- Repair of accessories 4

- Coil winding 5

- Connections 4

DISTRIBUTION

TRANSFORMER

EXCELEC DATA SHEETS






Repair/refurbishment in factory:

(continued)

- Work on magnetic core 5

- Active part reassembly 5

- Tanking 5

- Oil filling 4

- Oil filtration in factory During repair/ 4refurbishment in factory

- Electrical tests in factory 5

- Painting and coating 3


- Oil purification 5or regeneration

On-site repair/refurbishment: During repair/

- On-site diagnosis refurbishment in factory 4

- Preparation for untanking 4

- Untanking 4

- Expert appraisal 5

- Active part dismantling 5

- Calculation and design 4

DISTRIBUTION

TRANSFORMER





Repair/refurbishment in factory:

(continued)

- Refurbishment of accessories 3

- Coil winding 5

- Shipment of windings to site 3

- Connections 4

- Work on magnetic core 5

- Active part assembly During repair/ 5refurbishment in factory

- Tanking 5

- Oil filling operations 3

- Protection system checking 3

- Commissioning 4

- Oil purification 5and regeneration

- Destruction of 3polluted transformers

DISTRIBUTION

TRANSFORMER


EXCELEC DATA SHEETS





Oil analyses: Every year

- Oil sampling 2

- Basic analyses 3

- PCB content analysis 5

- Dissolved gas 5and furanic analyses

- Results interpretation 5

Maintenance: Every year

- Visual check (endoscopy) 2

- Oil sampling and analysis 2

- LV electrical testing 3

- Environmental checks 3(pollution and fires)

- Partial discharges 5

- HV electrical testing 5

- Noise test 3

- Infrared thermography 3

- Oil level (except for

integral-filling devices) 2

- Air dryer maintenance 2

- Air dryer replacement 4

- Dessicant breather replacement 2

DISTRIBUTION

TRANSFORMER





Maintenance (continued): Every year

- Check of transformer's 3protection systems

- Bushing cleaning Every year 2

- Transformer compartment Every year 2cleaning

- Visual check for leakage Every year 2

- Leakage repair if necessary 2

- Gasket replacement if necessary 4

- Bushing replacement if necessary 4

- Accessories check Every year 4

- Accessories replacement if necessary 3

- Refurbishment of auxiliary equipments if necessary 2

- Oil filtration if necessary 3

- Installation of retention tanks if necessary 4

- Installation of if necessary 3fire protection systems

- Transformer moving if necessary 3

- Painting if necessary 3

- Coating if necessary 3

- Oil retrofilling, purification if necessary 5and regeneration

DISTRIBUTION

TRANSFORMER


EXCELEC DATA SHEETS


GIS EQUIPMENT



Erection & Commissioning In case of re-assembly of 4supervision a component (circuit breaker,

disconnector, …)

after repair

Erection: In case of re-assembly of 2- GIS assembly under a component (circuit breaker,

responsibility of supervisor disconnector, …)

after repair

Dielectric tests/detection In case of re-assembly of 5of partial discharges: a component (circuit breaker,

- To validate re-assembly disconnector, …)

after repair after repair

IR thermographic check Every 5 years, energized 3

Optical indicators Every 5 years, de-energized 1operating check

SF6 filling valves Every year, de-energized 1& operating

mechanisms labeling

check

Cubicle heating resistors Every year, de-energized 1operating check

LV wiring connections Every 5 years, de-energized 2check

Mechanisms and alarms Every 5 years, de-energized 2check

Cubicle tightness Every 15 years, de-energized 1check

GENERAL


HV

GIS EQUIPMENT



Pressure check with Every year, when energized 1permanent pressure gauge

(if applicable)

Pressure check with Every 5 years, de-energized 1appropriate tool

SF6 quality check Every 5 years, de-energized 2

SF6 leakage pinpointing Every 5 years, de-energized 2

Density switch checking Every 5 years, de-energized 2(including wiring

connections), check from

control room

Operating time checks Every 5 years, de-energized 3(main and auxiliary

contacts)

Contact wear check Every 5000 operations, 4de-energized

Capacitor replacement Every 5000 operations 5or 25 years, de-energized

Circuit-breaker control Every 15 years, de-energized 3rod adjustment check

(if applicable)

Renovation and upgrading Every 20 years, de-energized 5

SF6

CIRCUIT BREAKERS


HV

GIS EQUIPMENT



Mechanical function Every 5 years, de-energized 3checks (locking,

interlocking, auxiliary

contacts)

Lubrication Every 5 years, de-energized 1

Contact inspection Every 5000 operations, 4de-energized

Mechanical function checks Every 5 years, de-energized 2(locking, interlocking,

auxiliary contacts)

Lubrication Every 5 years, de-energized 1

Leaking current measurement Every 15 years, de-energized 3

Reading of discharge Every year 1counters

DISCONNECTORS

EARTHING

SWITCHES

EQUIPMENT:

SURGE ARRESTORS


HV

EXCELEC DATA SHEETS


EXCELEC DATA SHEETS


POWER TRANSFORMER



Switching of off-load tap changer Every year, de-energized 1

Overall look: cleanliness, moisture Every year 1content and oxidation. Frequency: yearly

Search for leaks, Every week 1unusual noises, hot spots

Visual check on Every year 1HV-MV-LV bushings

Air dryer check Every year 1

Visual check on Every year 1electrical auxiliary cabinet

Oil level check Every 6 months 1

Check of the dessicant Every 6 months 1breather condition

Maintenance of air coolers /

water coolers:

- Heat exchanger cleaning Every year 2

- Beam cleaning Every year 2

- Motor-powered fan Every 5 years or upon failure 2

Dielectric oil analysis :

- Physico-chemical Every year 3

- Dissolved gas analysis Every year 3

- Particles counting, search for Every 5 years 3furfural and its derivatives

POWER TRANSFORMER


POWER TRANSFORMER



Check on HV and LV connections Every year 3

On-load tap changer:

- Operating and safety Every year 2checks

- Oil analysis Every year 3

- Complete overhaul of OLTC Every 5 years 4including replacement of parts

and oil (to be replaced every

50 000 or 100 000 operations

if circuit filtered permanently)

Check on transformer accessories:

- Oil level Every year 1

- Cooling system check Every year 2

- Filter clogging Every year 2

- Oil circuit check Every year 2

- Thermostat Every year 2

- Buchholz relay Every year 3

- RS 2000 and 2001 relays Every year 3

- Protection relays for Every year 3transformer and OLTC

POWER TRANSFORMER


POWER TRANSFORMER



Other maintenance work:

- Tank and pipes painting-coating Every year and maintenance 2work if necessary

- Oil filtration Every 5 years 3according to oil analyses

- Replacement or oil According to results,

retreatment dissolved gas

analyses

- Tan delta values on transformer Every 5 years or

or bushings on incident

- Replacement of HV/LV/N bushings As per Tan delta 4results

- Replacement of motor-powered fan According to 3insulation results

- Change of circulation pump 3

- Change of oil 3circulation indicator

- Replacement of thermometers 3

- Replacement of relief valve 3

- Replacement of Buchholz relay 3

Expert appraisal upon failure:

- Nature and origin of the failure 4

- Operating background 4analysis

Upon failure

- Oscilloperturbograph 4analysis

- Oil analyses (Buchholz gas, 3DGA, furfural, PCB

POWER TRANSFORMER


EXCELEC DATA SHEETS


EXCELEC DATA SHEETS


POWER TRANSFORMER



Expert appraisal upon failure (continued):

- Electrical measurement: 3• Ratios

• Resistance

• Impedance

• Insulation Upon failure

- Endoscopy 3- On-site expertise:

• Results interpretation 5• Definition of the type of repair

(on site, in workshop) 4and operating process

On-site repair:

- Without untanking 4Upon failure

- With untanking and expert 5appraisal of active part

Repair in factory (with untanking)

- Disassembly to view the fault 5+ validation of the repair

process

- Expert appraisal (causes Upon failure 5and origin of fault)

- Reassembly and tests 5

POWER TRANSFORMER


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