| Item A |
765 kV Capacitor Voltage Transformer (CVT) |
Unit |
SCHEDULE A |
SCHEDULE B |
| Eskom |
Technical |
| requirements |
guarantees for |
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equipment offered |
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| 1 |
Manufacturer |
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TYD765/√3-0.0044H |
| 2 |
Manufacturer's type number |
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| 3 |
Rated Capacitance |
pF |
4,400 |
4,400 |
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a) Value of upper capacitance (C1) |
pF |
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b) Lower Capacitance (C2) |
pF |
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| 4 |
System conditions for which the |
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capacitor shall be suitable |
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a) Rated frequency |
Hz |
50 |
50 |
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b) System neutral |
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Effectively earthed |
Effectively earthed |
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c) Rated r.m.s. line-to-line voltage |
kV |
765 |
765 |
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d) Maximum continuous r.m.s. line-to-line Voltage |
kV |
800 |
800 |
| 5 |
Insulation |
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a) Minimum crest value of full wave |
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lightning impulse type test withstand |
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voltage to earth at sea level on HV terminal |
kV |
2,100 |
2,100 |
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b) Characteristic of impulse wave |
μs |
1.2/50 |
1.2/50 |
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c) Minimum crest value of full wave |
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switching impulse type test withstand |
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voltage to earth at sea level on HV terminal |
kV |
1,550 |
1,550 |
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d) Characteristic of impulse wave |
μs |
250/2 500 |
250/2 500 |
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e) Minimum 60 s power frequency wet |
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withstand type test voltage to earth at |
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sea level on HV terminal |
kV r.m.s. |
975 |
975 |
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f) Minimum 60 s power frequency dry |
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withstand routine test voltage at sea level |
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on HV terminal |
kV r.m.s. |
975 |
975 |
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g) Partial discharge type test in accordance with |
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IEC 61869-1 |
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Complies |
Complies |
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h) Polution level |
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1) Extra heavy - creepage distances |
mm |
Extra heavy |
Extra heavy |
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arcing distances |
mm |
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| 6 |
Equipment suitable for carrier injection |
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Yes |
Yes |
| 7 |
High frequency capacitance and |
% |
-20 to +50 of rated C |
-20 to +50 of rated C |
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equivalent series resistance |
Ωmax |
40 |
40 |
| 8 |
Stray capacitance and stray conductance |
pF max |
200 |
200 |
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of low voltage terminals |
μs max |
20 |
20 |
| 9 |
Radio influence |
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a) Test voltage kV |
kV |
508 |
508 |
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b) Maximum radio influence voltage |
μV |
2500 |
2500 |
| 10 |
Self resonant frequency of complete capacitor stack |
MHz |
>1 |
>1 |
| 11 |
LV terminals |
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Minimum 60 s power frequency dry |
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withstand routine test voltage on low |
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voltage terminal |
kV r.m.s. |
10 |
10 |
| 12 |
Capacitor suitable for supporting a line trap |
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No |
No |
| 13 |
VT Secondary windings |
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a) Protection (P1) |
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1 |
1 |
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b) Protection (P2) |
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1 |
1 |
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c) Metering (M) |
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1 |
1 |
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d) Total |
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3 |
3 |
| 14 |
VT mounted in base of CC (Single unit) |
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Yes |
Yes |
| 15 |
Rated CVT transformation ratios |
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a) Protection winding (P1) |
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765/√3 kV to 110/√3 V |
765/√3 kV to 110/√3 V |
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b) Protection winding (P2) |
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765/√3 kV to 110/√3 V |
765/√3 kV to 110/√3 V |
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c) Metering winding |
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765/√3 kV to 110/√3 V |
765/√3 kV to 110/√3 V |
| 16 |
16 Rated burden of secondary windings |
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a) P1 winding |
VA |
50 |
50 |
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b) P2 winding |
VA |
50 |
50 |
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c) M winding |
VA |
50 |
50 |
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d) Total burden |
VA |
150 |
150 |
| 17 |
Accuracy class of CVT |
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a) P1 winding |
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3P |
3P |
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b) P2 winding |
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3P |
3P |
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c) M winding (within burden range 40 VA to 50 VA) |
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0.2M |
0.2M |
| 18 |
Transient response Class |
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T1 |
T1 |
| 19 |
Ferroresonance (Ref 5.15 of 240-56030645) |
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a) Amplitude |
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b) Damping |
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| 20 |
Secondary short circuit current |
A |
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a) P1 winding |
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b) P2 winding |
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c) M winding |
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| 21 |
Maximum CVT rating as a power transformer |
kVA |
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Cos φ |
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| 22 |
Recommended maximum rating of fuses |
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protecting the voltage transformer secondary windings |
A |
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| 23 |
Class of insulation of VT |
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| 24 |
Rated voltage factor |
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a) Continuous |
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1.2 |
1.2 |
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b) 30 |
s |
1.5 |
1.5 |
| 25 |
Temperature category of CVT |
°C |
-10 to +40 |
-10 to +40 |
| 26 |
Maximum carrier frequency insertion loss of VT |
dB |
0.5 |
0.5 |
| 27 |
Minimum 60 s power frequency withstand routine |
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test voltage on secondary windings |
kV r.m.s. |
2 |
2 |
| 28 |
CVT equipment with carrier earthing switch |
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Yes |
Yes |
| 29 |
Carrier drain coil |
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a) i) Maximum insertion loss |
dB |
0.5 |
0.5 |
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or |
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ii) Minimum impedance at carrier frequency |
kΩ |
10 |
10 |
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b) i) Maximum volt drop at rated frequency with |
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associated CC energized at rated voltage |
V |
30 |
30 |
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or |
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ii) Maximum 50 Hz impedance |
Ω |
20 |
20 |
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c) Minimum 50 Hz current carrying capacity |
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i) Continuous |
A r.m.s. |
1 |
1 |
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ii) Short time for 0.2s |
A r.m.s. |
50 |
50 |
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d) Minimum impulse withstand voltage |
kV |
10 |
10 |
| 30 |
Low voltage terminal arrester |
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Non linear arrester |
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Yes |
Yes |
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a) Rated voltage |
kV |
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b) Impulse sparkover voltage |
kV |
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c) Minimum 8/20 μs impulse discharge current |
kA |
5 |
5 |
| 31 |
Type of mounting |
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Upright on pedestal with |
Upright on pedestal with |
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integral VT as base unit |
integral VT as base unit |
| 32 |
High-voltage terminal |
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a) Terminal material and finish |
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b) Dimensions |
mm |
60 dia x 150 long |
60 dia x 150 long |
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c) Arrangement of terminals |
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Vertical |
Vertical |
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d) Number of terminals |
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1 |
1 |
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e) Withstand force without failure |
kN |
3 |
3 |
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f) Withstand force without distortion |
kN |
1.5 |
1.5 |
| 33 |
Secondary terminals |
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a) Separate terminal box for secondary terminals |
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with gland plate facilities |
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Yes |
Yes |
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b) Separate insulated bushing for connection to |
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carrier equipment |
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Yes |
Yes |
| 34 |
Mass of complete CVT |
kg |
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| 35 |
Outline Drawings showing: |
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a) dimensions, fixing details and mounting arrangements |
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Yes |
Yes |
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b) Details of HV connecting terminals |
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Yes |
Yes |
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c) Earth terminal |
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Yes |
Yes |
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d) Details of secondary terminal |
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Yes |
Yes |
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e) Details of earth switch and carrier connection |
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Yes |
Yes |
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f) Nameplate |
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Yes |
Yes |
| 36 |
Type test reports (Capacitor Voltage Transformer) |
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| a) Temperature-rise test |
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Yes |
Yes |
| b) Chopped impulse test |
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Yes |
Yes |
| c) Switching impulse test |
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Yes |
Yes |
| d) Wet test for outdoor type transformers |
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Yes |
Yes |
| e) Radio influence voltage test (RIV) |
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Yes |
Yes |
| f) Transmitted overvoltage test |
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Yes |
Yes |
| g) Test for accuracy |
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Yes |
Yes |
| h) Verification of the degree of protection by enclosures |
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Yes |
Yes |
| i) Enclosure tightness test at ambient temperature |
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Yes |
Yes |
| j) Capacitance and tan δ measurement at power frequency |
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Yes |
Yes |
| k) Short circuit withstand capability test |
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Yes |
Yes |
| l) Ferro-resonance test |
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Yes |
Yes |
| m) Transient response test |
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Yes |
Yes |
| n) Mechanical test |
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Yes |
Yes |
| 37 |
Type test reports (Carrier frequency accessories) |
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| a) Drain coil - Impulse voltage test |
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Yes |
Yes |
| b) Drain coil - Voltage withstand test |
|
Yes |
Yes |
| c) Voltage limitation device - Impulse voltage test |
|
Yes |
Yes |
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