Schneider HV Metering Unit with Open Delta (5 Limb) Test Form / Document Number: ECP 11-0515d
Version: 3.0
Date: 27/06/2018

Schneider HV Metering Unit with Open Delta (5 Limb) Test Form

Note: This form is based on drawingRMSCH-MU6-N37 Rev C; the terminal, fuse and link designations on units built to earlier revisions may differ.

Full Postal Address
Import MPAN
Export MPAN
Substation Name
Substation Number
Metering Unit Serial No
Metering Unit Make Type / Schneider MU6-N37
System Configuration / 3-PHASE 3-WIRE
CT / L1 / L2 / L3
Location / METERING UNIT / METERING UNIT / METERING UNIT
Serial Number**
Burden (output VA) ** / VA / VA / VA
Accuracy Class / 0.5 / 0.5 / 0.5
Make **
Type / WOUND / WOUND / WOUND
Available Ratios / 400/200/5A / 400/200/5A / 400/200/5A
Ratio Selected / A / A / A
Pole P1 Facing Distribution System? / YES / NO * / YES / NO * / YES / NO *
VT / L1 / L2 / L3
Location / METERING UNIT / METERING UNIT / METERING UNIT
Serial Number ***
Burden (output VA) *** / VA / VA / VA
Accuracy Class / 0.5 / 0.5 / 0.5
Make***
Type / 3P / 3P / 3P
Available Ratios / 11000/6600/110V / 11000/6600/110V / 11000/6600/110V
Ratio Selected / V / V / V
* Delete as applicable. ** Available from CT label. *** Available from VT label.

Voltage Transformer Tests

VT Configuration Checks
Check metering multi-core cable disconnected / ()
Check correct metering VT ratio selected (terminals 11 to 19) see TABLE 1 below / ()
Ensure label on lid of terminal box matches VT voltage ratio selected / ()
Check correct NPD VT ratio selected (terminals 25 to 33) see TABLE 2 below / ()
Check 110V auxiliary fuse F1 rating is 2A and continuity / ()
Check VT fuse F2 and F3 ratings are 6A and continuity / ()
Check NPD fuse F4 rating is2A and continuity / ()
Check white LV links LK4, LK5, LK7 are installed / ()
Check secondary earth links LK6 and LK8 (terminal 37) are installed / ()
TABLE 1 Metering VT Voltage Range Selection
Phase / Metering VT 6600/110V / Common Terminal / Metering VT 11000/110V
L1 / E110 (terminal 11) / E10 (terminal 12) / E210 (terminal 13)
L2 / E130 (terminal 14) / E30 (terminal 15) / E230 (terminal 16)
L3 / E150 (terminal 17) / E50 (terminal 18) / E250 (terminal 19)
TABLE 2 NPD VT Voltage Range Selection
Phase / NPD VT 11000/110V / Common Terminal / NPD VT 6600/110V
L1 / da2-L1 (terminal 26) / E87 (terminal 27) / da1-L1 (terminal 28)
L2 / da2-L2 (terminal 29) / dn-L1 (terminal 30) / da1-L2 (terminal 31)
L3 / da2-L3 (terminal 32) / dn-L2 (terminal 33) / da1-L3 (terminal 34)
VTPrimary Winding Resistance Tests
Measure the resistance of the VT L1 primary winding (L1 to Earth) * / k
Measure the resistance of the VT L2 primary winding (L2 to Earth) * / k
Measure the resistance of the VT L3 primary winding (L3 to Earth) * / k
All phase to earth values similar / ()
Measure the resistance of the VT L1 to L2 primary winding * / k
Measure the resistance of the VT L2 to L3 primary winding * / k
Measure the resistance of the VT L3 to L1 primary winding * / k
All phase to phase values similar All phase to earth values similar / ()
* Measure from the HV bushing or busbar in HV metering unit to earth using a multimeter, the resistance of the star connected VT to earth is 2 to 4kΩ and 4 to 6kΩ between phases.
VT Insulation Resistance – 1kV Insulation Resistance Tester
Remove secondary earth white link LK6 and link LK8 (terminal 37) / ()
Measure insulation resistance of metering VT secondary (across white link LK6) / M
Measure insulation resistance of NPD VT secondary (across terminal 37) / M
Replacewhite link LK6 and link LK8 (terminal 37) / ()
VT Phasing Check – Primary Injection
Remove fuses F2, F3 and F4 / ()
Remove white links LK5 and LK7 / ()
Check the metering circuit breaker is open / ()
Apply 240/110V ac from an injection test set to the primary (HV) winding, measure each of the secondary (LV) winding voltages and compare to the values in the table below*
Primary (HV) Winding / Secondary (LV) Winding Voltage (measured at fuse/link)
Voltage / Bushing / NPD**
F4 – LK7 / L1 – L2
(F2 – LK5) / L2 – L3
(LK5 – F3) / L1 – L3
(F2 – F3)
L1 L2 / V / V (nominal) / V / V
L2 L3 / V / V / V (nominal) / V
L3 L1 / V / V / V / V (nominal)
Replacewhite linksLK5 and LK7 / ()
Replace6A fuses F2 and F3 / ()
Replace2A fuse F4 / ()
* These voltages are for an injection test set and if a mains supply is used the results may differ.
** The NPD voltage measured should be in the order of 0.2to 2V.
VT Primary (HV) Rated Voltage / VT Nominal Secondary (LV) Winding Voltage with 240/110V applied to the Primary (HV) Winding
240V / 110V
11kV / 2.4V / 1.1V
6.6kV / 4.0V / 1.8V

Current Transformer Tests

CT Insulation Resistance – 1kV Insulation Resistance Tester
Check CTs isolated or HV dead / ()
Measure the insulation resistance (D70 – D90 at terminal 10) / M
Disconnect CT star point earth (terminal 10) / ()
Measure the insulation resistance (D70 – D90 at terminal 10) / M
Reconnect CT star point earth (terminal 10) / ()
CT Polarity – Flick Test
Open CT shorting-links (terminals 1 and 2) / ()
Check L1 phase CT polarity – D11 at terminal 1 (+ve) to D70 at terminal 10 (-ve) / ()
Check L3 phase CT polarity – D51 at terminal 2 (+ve) to D70 at terminal 10 (-ve) / ()
CT Ratio Check – Primary Injection or Prevailing Load*
Phase / CT Ratio
Primary Current / CT Ratio Secondary Current / Injected Primary Current* / Calculated Secondary Current / Term / Measured Secondary Current / Ratio Correct
[A] / [B] / [C] / [D = B/ A* C] / [E] / [E = D]
L1 / 200A / 5A / 50 / 100A / A / A / 1-10 / A / ()
L3 / 200A / 5A / 50 / 100A / A / A / 2-10 / A / ()
L1 / 400A / 5A / 50 / 100A / A / A / 1-10 / A / ()
L3 / 400A / 5A / 50 / 100A / A / A / 2-10 / A / ()
On completion of test ensure correct CT ratio low (200A) or high (400A) as specified by designer is selected / ()
* Delete as applicable.
CTRelationship to VT Output at Terminal Box
L1 CT associated with L1 voltage ** / ()
L3 CT associated with L3 voltage ** / ()
**If all CT and VT tests are correct the CT relationship to the VT is proven and the above can be ticked
CT and VT Burden / CT / VT
Maximum burden per phase at metering unit terminal box / 0.5 / VA / 0.05 / VA
Maximum burden per phase at meter terminal box[1] / 7.5 / VA / 0.1 / VA
Final Checks
Reconnect metering multi-core cable (if disconnected) / ()
If metering multi-core cable is not connected leave CTs shorted – close shorting links (terminals 1 and 2) / ()
Check all covers are secured and appropriate lock fitted to lid / ()
Complete asset data form and submit to ART / ()
Test Equipment
Purpose/Make/Type / Serial Number / Calibration Expiry Date
Certification
CT and VT calibration certificates attached / ()
All tests completed satisfactorily / ()
Comments
Organisation / Test Operative Name
Date of Tests / Test Operative Signature

A copy of the completed test form together with the CT/VT calibration certificates shall be placed in a plastic wallet in the metering unit terminal box.

A copy of the completed test form and the CT/VT calibration certificates shall be sent to the relevant ART mailbox (, , ).

A copy of the completed test form and the CT/VT calibration certificates shall also be attached to the relevant operation on the work order or the relevant PO in the contractor portal.

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© UK Power Networks 2018 All rights reserved1 of 6

Schneider HV Metering Unit with Open Delta (5 Limb) Test Form / Document Number: ECP 11-0515d
Version: 3.0
Date: 27/06/2018
Figure 1 – Schneider MU6 Metering Unit / Figure 2 – Terminal Box with Cover Removed
Figure 3 – Fuses and Links / Figure 4 – Terminal Block
Figure 5 – CT Labels / Figure 6 – VT Labels

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Schneider HV Metering Unit with Open Delta (5 Limb) Test Form / Document Number: ECP 11-0515d
Version: 3.0
Date: 27/06/2018

[1] The maximum burden is based on 20 metres of 12-core 2.5mm2 or 40 metres of 19-core 2.5mm2 copper cable with a resistance of 0.0068 Ω/m at 20oC and a CT rated secondary current of 5A.