Tenaga Nasional Berhad
Tenaga Nasional Berhad
Tenaga Nasional Berhad
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2.2.1 Adopted Security Level Definitions For TNB Distribution Systems<br />
Table 2-3: Security Levels for Distribution Network<br />
Security Level<br />
Level 1<br />
Level 2<br />
Level 3<br />
Level 4<br />
Average Restoration Period<br />
Less than 5 seconds<br />
Less than 15 minutes<br />
Less than 4 hours<br />
Less than 24 hours<br />
2.2.2 Supply Security Level to Consumers<br />
For supplies to consumers at voltage levels of 6.6kV, 11kV, 22kV and 33kV, large part of the network are generally<br />
designed to facilitate an average supply restoration of less than 4 hours. For supplies at 240V and 415V, the restoration<br />
period may vary beyond 4 hours depending on the type of network fault.<br />
2.2.3 Request for Higher Supply Security Level<br />
However, TNB can design the supply scheme to meet higher security level requirement of individual consumer or group<br />
of consumers. All additional costs involved in providing the higher security level shall be borne by the consumer.<br />
2.3 POWER QUALITY<br />
2.3.1 Power Quality Requirements<br />
2.3.1.1 The electromagnetic disturbance covers the following phenomena:<br />
a. Voltage fluctuations and flickers<br />
b. Harmonics up to order of 50 th<br />
c. Voltage dips and short supply interruptions<br />
d. Voltage unbalance<br />
e. Inter-harmonics up to 50 th<br />
f. Voltage distortions at higher frequencies (above 50 th harmonics)<br />
g. Transient overvoltages<br />
h. Power frequency variation<br />
i. Dc components<br />
j. Mains signaling<br />
30 TENAGA<br />
NASIONAL B E R H A D
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