Voltage Drop Test in HV Cables
Voltage Drop Test in HV Cables
(OP)
I have to test the actual voltage drop in an 11kv cable, the cable is a 185mm2/cu/3core/xlpe/pvc, 1500mtrs long.
Has anyone carried out such a test and what equipment did you use??
Has anyone carried out such a test and what equipment did you use??






RE: Voltage Drop Test in HV Cables
OTOH, measurement of voltage change via met-lab grade PTs on the ends of the cable would accommodate actual load power factor and dynamic characteristics. Can you give some more details on what is expected from the test? At the extreme, it could get as complex as full GPS-synched ø-ø and ø-g readings at the cable ends. Research physicists can come up with some requests for screwy electrical measurements when there’s enough money in the budget.
RE: Voltage Drop Test in HV Cables
The 'Actual Voltage Drop' is defined as the end to end drop in voltage under start and full running load conditions.
I have contacted cable manufacturers in UK,Saudi and Kuwait, all tell me that they don't actually carry out a VD test to determine values for thier published cable data but rather rely on calculation.
I have considered making use of a suitable PT/recorder at the remote end of the cable during operation but am looking for other, less drastic, methods
RE: Voltage Drop Test in HV Cables
#1 - Do calculation. This can be a little involved but there are well-established methods.
#2 - Measure the phase-to-ground voltage during operration on one or all phases using PT's at both ends. As busbar points out, this will only tell you the magnitude of voltage drop, but not the phase of the impedance (that would require comparing phase across the cable).
RE: Voltage Drop Test in HV Cables
If by some rare chance the arithmetic is correct, ~85 amperes at ~24 volts would emulate a motor running state. Roughly six times those figures would mimic a starting condition. A full-tilt three-phase test would invariably be more complex. It’s conceivable that some error would be introduced in being unable to extrapolate actual X/R ratios.
RE: Voltage Drop Test in HV Cables
1. The magnitude of voltage at the end of cable as a difference between |Vcablesendingend|-|Vcablereceivingend|=V/D1; or
2. The magnitude of voltage across the cable as |Vcablesendingend - Vcablereceivingend|=V/D2.
Generally, V/D1 is different (smaller) from V/D2.
RE: Voltage Drop Test in HV Cables
If for purposes of determining how the bus voltage will be affected (affect on starting and remaining motors), calculation is generally used and should be accurate enough.
RE: Voltage Drop Test in HV Cables
If anyone has carried out sutch a test, without using PT's and recorders at each end of the cable, I should be most grateful for some advice.
Regards
J
RE: Voltage Drop Test in HV Cables
RE: Voltage Drop Test in HV Cables
RE: Voltage Drop Test in HV Cables