In electrical cables what is U and U0 refers?
Answers were Sorted based on User's Feedback
Answer / sivasubramanian
U0 is the r.m.s. value between any insulated conductor and
earth , i.e. metal covering of the cable or the surrounding
medium;
U is the r.m.s. (root mean square voltage) value between
any two phased conductors of a multicore cable or of a
system of single core cables.
Is This Answer Correct ? | 54 Yes | 3 No |
Answer / jeffrey tay
U0 is the rated power frequency voltage between conductor
and earth or metallic screen for which the cable is designed
U is the rated power frequency voltage between conductors
for which the cable is designed
Um is the maximum value of the “highest system voltage” for
which the equipment may be used (see IEC 60038)
Is This Answer Correct ? | 26 Yes | 3 No |
Answer / lalit
Uo is the phase ground voltage and
U is the phase - phase voltage
Is This Answer Correct ? | 5 Yes | 0 No |
Answer / kannan
Rated voltage is a reference voltage used for cable design
and electrical property test, and identified with Uo/U and
Um in the standard. The meaning of the symbols is defined as
per JB/T 8996.
Uo一Virtual value of the rated voltage between conductor
used for cable design and metallic shield or metallic
sheath, kV;
U一Virtual value of the rated voltage between conductors
used for cable design, kV;
Um一Virtual value of the highest working voltage for
equipment, kV.
In the standard: Uo/U=64/110
Um=126
Is This Answer Correct ? | 2 Yes | 0 No |
Answer / jeffrey tay
U0 is the cable conductor and shield design with metal
cover layer or between the rated power frequency voltage; U
is a cable designed for use between conductors rated
frequency voltage (three-phase line voltage); Um is the
maximum operating voltage of the system; Up is cable
designed for use in each line of core and shield or metal
sleeve Lightning impulse withstand voltage between the
peak.
U0 value is based on cable systems where the single-phase
ground fault occurs when the duration of the permit
determined. In the GB 12706. 1 -91 stipulated in the two
types of cables: Category 1 cables, U0 for 21 kV, for each
single-phase ground fault time is not greater than 1 min of
the system can be used for single-phase ground fault time
of the most length of no more than 8 h, an annual total of
no more than 125 h of the system; Class 2 cable, U0 for 26
kV, for a longer ground fault systems, and cable insulation
performance requirements for high occasions.
Is This Answer Correct ? | 5 Yes | 5 No |
Answer / essam s. salib
Uo in under ground cables is the voltage between any phase and the sheath surrounding the cable, while Uo in OH lines is the voltage between any phase and the ground through the line stray capacitance.
U is the voltage difference between any two phases either cables or OH lines.
Um is the maximum operating line voltage between phases
Is This Answer Correct ? | 1 Yes | 1 No |
Answer / will
U -means the voltage at that instance.
Uo-means the nominal voltage or design voltage.
Is This Answer Correct ? | 15 Yes | 42 No |
what is meant by flywheel and its role in retardation test
What is the principle of residual protection?
What are diffrent type of road taxes?
what is the difference betwteen overcurrent and short circuit fault?
Why should we hire you over the others waiting to be interview?
The power factor of the fixed load is 0.8, now the p.f is varying from 0.8 to 0.5.
Why electric traction is used ??
why for transformer protection we protect tranformer from 3rd hormonics and 5th hormonics and what is the reason of generating these horminics in electrical system?
what is inverter
Why in power plant projects we see DOL starting method used for motors upto 160 kW instead of star delta method
how tto ingress mw in turbine explain.procedure ?
A powerplant has 8 gensets operating in grid parallel mode. In one genset sometimes there is pf variation and kvar variation. The plant operates in pf mode. When this variation is observed the load is stable, voltage is also stable, freq and genset speed is also stable. How will you check the functioning of pf card. What shall be the ideal output vdc of the pfc, from there it is input to AVR?