35 kV and Below INTERCONNECTION REQUIREMENTS - BC Hydro
35 kV and Below INTERCONNECTION REQUIREMENTS - BC Hydro
35 kV and Below INTERCONNECTION REQUIREMENTS - BC Hydro
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4.1.2 Generator Distribution Line Protection<br />
Revision Date: May 2010<br />
<strong>35</strong> <strong>kV</strong> <strong>and</strong> <strong>Below</strong> Interconnection Requirements for Power Generators<br />
Since the PG contributes to faults on the <strong>BC</strong>H system, the PG shall provide equipment to clear phase <strong>and</strong><br />
ground faults on the <strong>BC</strong>H distribution line. This protection is generally referred to as ‘Distribution Line<br />
Protection.’ Required fault clearing times will be specified by <strong>BC</strong>H.<br />
The generation facility must be able to detect the following situations in the <strong>BC</strong>H feeder <strong>and</strong> isolate itself<br />
from the distribution system:<br />
(a) a short circuit between any phase(s) <strong>and</strong> ground,<br />
(b) a short circuit between phase(s), or<br />
(c) loss of any phase(s).<br />
Single-phasing of the three-phase primary service to a PG can occur due to broken conductors <strong>and</strong>/or<br />
protective equipment operation <strong>and</strong> the PG shall take measures to protect its plant.<br />
The PG shall provide breaker failure protection for plants rated 1 MVA <strong>and</strong> up, via:<br />
(a) CB auxiliary switch scheme, or<br />
(b) current-based scheme, or<br />
(c) remote back-up coverage via other relaying within the PG plant.<br />
4.1.3 Equipment Rating<br />
The PG's equipment shall be rated to carry <strong>and</strong> interrupt the fault levels that are or will be available at the<br />
PG’s location - this includes the ultimate fault currents specified by <strong>BC</strong>H. The PG's equipment includes all<br />
its station <strong>and</strong> distribution facilities, including but not limited to all protection equipment forming the<br />
entrance <strong>and</strong> distribution line protection: current transformers, potential transformers, secondary cabling,<br />
dc system/battery charger, switchboard wiring <strong>and</strong> protective relays. If the equipment supplied is not<br />
designed for the ultimate fault duty, the PG assumes the responsibility for upgrading when necessary to<br />
accommodate changes to the system <strong>and</strong> the PG is responsible for contacting <strong>BC</strong>H to ensure their<br />
equipment is suitably rated. Ultimate fault levels are:<br />
Table 1: Interrupting Ratings<br />
Type of 3-Phase<br />
Service<br />
Circuit Breakers &<br />
Reclosers<br />
Fuses Fuses<br />
Symmetrical MVA Asymmetrical rms<br />
Amperes<br />
4.16 <strong>kV</strong>, 4-Wire 50 12,000 7,500<br />
12.5 <strong>kV</strong>, 4-Wire 250 20,000* 11,500*<br />
25 <strong>kV</strong>, 4-Wire 500 20,000* 11,500*<br />
34.5 <strong>kV</strong>, 4-wire 300** 9,000 5,000<br />
Symmetric rms<br />
Amperes<br />
* where fuses are permitted <strong>and</strong> installed on outdoor pole top installations, the PG may install 12,000 A<br />
asymmetric cutouts (8,000 A symmetric),<br />
** <strong>BC</strong> <strong>Hydro</strong> <strong>35</strong> <strong>kV</strong> distribution is stepped up from 25 <strong>kV</strong> in the field.<br />
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