Megger DELTA 4000, Справочное руководство

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ZM-AH02E DELTA 4000 31
3 TESTING POWER SYSTEM COMPONENTS
Measurement Intercheck
Capacitance C
1
= C
3
- C
2
Watts: W
1
= W
3
- W
2
Note: Subscripts are test no.’s.
B1 & B2 Entrance bushings
C1 & C2 Grading capacitors
D
Module live tank
I1 Upper insulator
I2 Lower insulator
I3 Insulator for units without current transformer
R Glass fiber air supply tube, open rods and wood tie
rods
T Current transformer insulation
I4 and I5 Protective glass fiber tube that encloses R tube is slit at
“E” with metal guard ring
Table 3.8
Live tank circuit breaker test connections (Typical
three-column support per phase)
Te
st
N
o
.
In
su
la
ti
o
n
te
ste
d
Φ
Low voltage lead
configuration
Test
connec-
tions to
breaker
R
em
ark
s
Te
st
m
o
d
e
M
ea
sur
e
G
ro
un
d
G
uar
d
H
ig
h
v
o
lt
ag
e
Re
d
B
lu
e
1 C1 UST-R Red Blue B A C C Grounded
2 C2 UST-B Blue Red B A C A Grounded
3 S1 GSTg-RB
Red
&
Blue
B A C A & C Guarded
4 C3 UST-R Red Blue D C E E Grounded
5 C4 UST-B Blue Red D C E C Grounded
6 S2 GSTg-RB
Red
&
Blue
D C E C & E Guarded
7 C5 UST-R Red Blue F E G G Grounded
8 C6 UST-B Blue Red F E G E Grounded
9 S3 GSTg-RB
Red
&
Blue
F E G E & G Guarded
A, C, E & G Low lead test connections
B, D, F
Module live tanks
C1 thru C6 Module entrance bushing and grading capacitors
L1, L2 Connection links joining modules
S1, S2, S3 Module support columns
Note: To reduce the effects of severe electrostatic interference,
disconnect one side of L1 and L2 links to break circuit between
modules. All terminals and bus work not in measurement circuit
must be solidly grounded.
Test procedure
Tests are performed at 10kV or a voltage suitable for the
insulation rating.
1]
All tests are conducted with the breaker in the
open position.
2]
Identify each set of readings with the apparatus se-
rial number. Enter the manufacturer, type or model
and other nameplate ratings. Note any special or
unusual test connections or conditions.
3]
Enter ambient temperature and relative humidity
and a general indication of weather conditions at
the time of the test.
4]
Record actual test voltage, current, watts, power
factor and capacitance. Correct current and watts
to a standard test voltage 10 kV if necessary.
5]
Unless specifically noted, power factor readings do
not need to be temperature corrected.
Test results
▪
High power factor readings on entrance bushings or
grading capacitors may be the result of deteriorated
grading capacitors or, in some cases, surface leakage. If
higher capacitance values occur, compared to prior tests,
it could be the result of short-circuited sections of the
grading capacitor.
▪
High losses on the column structure could be the result of
moisture or surface leakage.
▪
Test results for power factor and capacitance are
significantly different between manufacturers, model
numbers, style, type and date the apparatus was
manufactured. Test data should be compared to the
manufacturers’ data. If nameplate or factory readings
are not available, compare the results of prior tests on
the same apparatus and results of similar tests on similar
apparatus.
SF
6
Circuit-breakers
These totally enclosed circuit-breakers, insulated with SF
6
gas (Sulfur Hexafluoride), are used whenever space is at a
premium, such as in downtown substations. They are much