Transmission Network Performance Report 2005 - National Grid

Transmission and CustomersFY20052 TRANSMISSION AND CUSTOMERSThis section focuses on the impact of transmission performance on itscustomers. There are several types of transmission customers. Some may beaffected by momentary outages for a few seconds, while some may suffer aprolonged disturbance due to a sustained outage.Loss of generation events impact system reliability directly through transmissionimpact and also contingency effects; both serve to disrupt the wholesale market.When transmission or distribution customers lose supply due to a sustainedtransmission outage, it is considered a loss of supply event. Loss of Supply andLoss of generation events impact customers and are therefore given particularlyhigh priority. These events are analyzed closely and all possible efforts are takento minimize their occurrence.2.1 Loss of Generation• For FY2005, there were 20 Loss of Generation incidents, 10 in NewEngland and 10 in New York. Loss of Generation applies only if agenerator is online at the time of the outage. All loss of generation eventsare captured regardless of the size of generation lost. In FY2005, theLosses in Generation ranged from 3 MW upwards.• The following figure indicates the number of Loss of Generation events inFY2005. This trend is compared against that of FY2004. Theimprovement in FY2005 over FY2004 is 23%.Figure 2-1: Cumulative LOG Incidents - FY2005 vs. FY20043025Number of LOG Incidents20151050Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb MarFY2004FY200516 National Grid Performance Report