Version: 3.0
Date: 30/01/2017
Transformer (and Reactor) Test Form
Substation NameSubstation Number
Circuit
General Data
Serial Number
Manufacturer
HV / LV1 / LV2 / Tertiary
Rating - CER / MVA
Rating - OFAF/ONA / MVA
Rating - ONAN(ON) AN / MVA
Nominal Voltage / kV
Full Load Current (normal tap) / A
Vector Group
Impedance % / HV/LV or HV/LV1
HV/T or HV/LV2
LV/T or LV1/LV2
Tapping Range (+% to -%) / in steps of / % HV/LV Winding
General Checks / HV / LV
Co-ordinating gap electrodes positioned correctly / mm
Setting of co-ordinating gap / mm
Setting of bushing arcing horn gap (below 132kV) / mm
All bushing and oil filled chambers oil levels correct
Air release plugs vented
Pressure relief diaphragm intact
Earthing connections satisfactory
All protective covers and shields fitted
All insulators undamaged and clean
Complete transformer oil tight
Painting visually satisfactory
All rating, diagram, identification plates, etc. fitted and satisfactory
Tightness of all fastenings
Dehydrating breathers satisfactory and pipework joints tight*
Refrigeration breathers satisfactory and pipework joints tight*
All cabling and wiring visually satisfactory
Kiosk and cubicle heaters operating satisfactorily
Interposing current transformers fitted and wired correctly
All compartments clean and tidy
All valves in correct operational position
All blanking plates satisfactory and correctly stored
General Tests
Core Primary Insulation / ( or n/a)
Core (2000V AC or 2500V Insulations Resistance Tester)
Core to clamping structure (MΩ at…..)
Windings Primary Insulation / ( or n/a)
Insulation resistance 100V DC (MΩ at……..)
HV / To all other windings, core frame and tank connected together & earthed
LV1
Tertiary or LV2
Ratio and Magnetising Current Tests
Ratio checked at all taps, and voltage continuity during tap changing. At the same time HV magnetizing current measured on maximum, normal and minimum tapping positions (with a 3-phase 4-wire low voltage supply connected to HV terminals and star point, with normal earth connection to star point disconnected).
Tap Number / HV Voltage (V) / HV Magnetising Current (mA) / LV1 Voltage (V) / Tertiary or LV1 Voltage (V)
A-N A-B / B-N B-C / C-N C-A / A / B / C / a-N a-b / b-N b-c / c-N c-a
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Vector Group Check
Connect one HV terminal to one LV (or Tertiary) terminal. With the transformer on nominal tap measure the following voltages, as necessary.
HV - LV1
A-a2 / A-b2 / A-c2
B-a2 / B-b2 / B-c2
C-a2 / C-b2 / C-c2
HV - LV2 or Tertiary
A- / A- / A-
B- / B- / B-
C- / C- / C-
Vector symbol from test
Checking vector groups according to BS 171
BS 171 Vector Group / Vector Diagram / Combination of HV and LV sides for comparison / Connection for measuring of vector position
HV / LV
Dd0 / / / Connect A to a. Energise terminals ABC with three phase voltage. Measure between Bb, Cc, AB, Bc
Voltage relationship:
1. Bb = Cc
2. Bb < AB
3. Bb < Bc
Yy0
Dz0
Dd6 / / / Connect A to a. Energise terminals ABC with three phase voltage. Measure between Bb, Cc, AB, Bc
Voltage relationship:
1. Bb = Cc
2. Bb > AB
3. Bb > Bc
Yy6
Dz6
Dy1 / / / Connect A to a. Energise terminals ABC with three phase voltage. Measure between Bb, Cc, AB, Bc
Voltage relationship:
1. Bb = Cc
2. Bb < AB
3. Bb < Bc
Yd1
Yz1
Dy11 / / / Connect A to a
Energise terminals ABC with three-phase voltage
Measure between Bb, Cc, AB, Cb
Voltage relationship
1. Bb = Cc
2. Bb < AB
3. Cc < Cb
YD11
Yz11
Vector and Phasing Diagrams
Substation
Transformer Number
Voltage Ratio
MVA Rating
Group Reference to BS 171
Engineer Signature
Date
Vector Diagram
Primary HV / Tertiary or Secondary LV2 / Secondary LV
Phasing Diagrams Transformer
HV Phase Colours
HV Terminal Markings
Note:
- Mark position of cable boxes if fitted.
- Mark position of neutral terminals.
- Mark position of tertiary terminal and identify.
LV Terminal Marking
LV Phase Colours
LV Switchgear - incoming connections looking at the front
LV Busbars - arrangements and incoming phase colours looking at the side / Back / Front
Motors and Overload Devices of Pumps, Fans and Tap Changer
Motor / Overload Device
Direction of Rotation Correct / Rated Current / Set at / Maximum Trip Operation Time
A / s / Starting with one fuse removed / Running and one fuse removed
Tap changer
Pumps
Fans
Note: The above checks shall apply to individual motors and each phase of individual overload devices. The values tabled shall be the maximum for any type of motor.
Buchholz Device / Transformer / Tap Changer
Serial Number
Manufacturer
Type
Inclination (degrees) / Longitudinal (3-7)
Lateral (0-5)
Quantity of air to operate / ml to make
Alarm contacts / ml to break
Approx. minimum air pressure to operate surge contacts and type of equipment used
Check surge and gas contacts stable when starting coolers, auto and manual with oil cold, and when pipework vibrates etc. State oil temperature
Temperature Indicators
Number 1 / Number 2 / Number 3
Manufacturer
Serial Number
Associated Winding
Contact / Function / Setting / Function / Setting / Function / Setting
Contact Function & Setting
WTI Heater Coil Circuits
Note, where tests have been carried out at the Contractor’s works, these are required only as approximate check tests
Number 1 / Number 2 / Number 3
CT Ratio
Ratio confirmed on load or by primary injection (record results on test form ECP110303)
Heater coil resistance / Nominal
ONAN / OFAF / ONAN / OFAF / ONAN / OFAF
Shunt resistance across heater coil /
Heater coil test: current injected (FLC) / A
Top oil temperature / °C
Initial temperature / °C
Steady temperature after minutes / °C
Temperature increment / °C
Calibration test on WTI indications and adjustment on repeaters
Number 1 WTI / Number 2 WTI / Number 3 WTI
WTI / Test Temperature / °C
Indicator Reading / °C
Repeater / Indicator Reading / °C
Repeater/Telecontrol Reading / °C
Inspection of Site Wiring / ( or n/a)
Insulation (see test forms ECP 11-0301 and ECP 11-0217)
Kiosk, tap change and cooling equipment wiring checked to: / Circuit Diagram Number …………………………………..
Revision ......
Wiring Diagram Number …………………………………..
Revision ......
Operational Tests
Tap Change Equipment / ( or n/a)
Raise / Lower
Maximum interval between operating times of Diverter Switches of single phase tap changers*
Local raising and lowering (full range)
Remote raising and lowering (full range)
Local/Remote Switch
Stepping Relay
Hand operation and handle interlock switch
Check maintaining circuit for correct sequence
Limit switches proved (in motor and control circuits)
Mechanical position indicator
Remote electrical position indicator including accurate indication of all positions
Tap Change Incomplete Alarm including accurate indication of all positions
Tap Change Counter operates correctly
Tap Change Counter Reading Initial/Final
Cooling Equipment
Operations, Alarms & Indications / Cooler A / Cooler B / Cooler C
Cooler control switch
Auto control from WTI
Time delay for pumps (Auto) / s
Time delay for pumps (Manual) / s
Differential pressure alarm
Pump failure alarm
Auto-start of standby pump
Stand-by pump running indication
Cooler fail alarm
Fuse ratings correct
Refrigeration Breather
Check freeze/thaw cycle in accordance with Manufactures instructions
DC Operations / ( or n/a)
Plant Terminal Block / Flag Relay
Surge trip
Gas alarm
Winding temperature indicator 1 trip
Winding temperature indicator 1 alarm
Winding temperature indicator 2 trip
Winding temperature indicator 2 alarm
Winding temperature indicator 3 trip
Winding temperature indicator 3 alarm
Breather device fail alarm
Oil Test / ( or n/a)
Oil samples from top and bottom of tank, also tap change compartments. These shall be taken in an approved manner to prevent oil being in contact with atmosphere.
Oil supplier
Oil samples tested
Comments
Test Equipment
Purpose / Make/Type / Serial Number
Certification / ()
All tests have been completed satisfactorily
Contractor Commissioning Engineer (if applicable)
Organisation / Name
Date / Signature
UK Power Networks Commissioning Engineer
Name / Signature / Date
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