Ingenieur Vol. 75 ingenieur July 2018-FA - Page 20

INGENIEUR have high fault currents breaching the safety factor of 90% of the VCBs and in some instances, even breaching the 20 kA rating of the VCBs. However, when the Main Substation reaches firm loading, i.e. the load is more than 50% of the transformer capacity, the utility opens the bus section between the transformers, effectively reducing the fault current to almost half its value. However, the practice is not to open the bus section unless the Main Substation has reached firm loading due to reliability concerns. Another option is to replace the 11 kV VCBs with higher ratings, say 25 kA. This will entail a substantial cost on the part of the utility, which will eventually be passed on to the consumers through tariff adjustments. GUIDELINES ON NEM AND SELF- CONSUMPTION BY EC The EC has come up with various guidelines on LSS, NEM, self-consumption, etc., especially on requirements for utility approval. There have been some accusations by the RE Industry that some of these guidelines appear one-sided. This is especially so since no engagement with the Industry or other stakeholders was held before the release of these guidelines. 6 18 VOL VOL 75 55 JULY-SEPTEMBER JUNE 2013 2018 THE WAY FORWARD Many countries in the region, including Singapore, have allowed for competition at the retail level. Many utilities now only own and operate the Transmission and Distribution (T & D) systems while generation and retail are open to bidding. To put Distributed Generation on a firm footing, the country will need to decide whether we still need a monopolistic, vertically integrated utility in the 21 st century. Many of the obstacles to further increase the contribution of RE generators can be overcome by opening Distribution and Retail to open competition. All new developments can be allowed to choose their electricity provider, who will buy from the utility at a higher voltage and distribute in their development at a lower voltage. Of course, these arrangements must make financial sense, so that the small distributor can make a reasonable margin to stay in business. These developments will certainly try to maximize the generation of electricity onsite, especially using RE sources, and only purchase the balance from the utility. There should be no subsidy schemes for RE in the long run, and the utility should be allowed to make a reasonable profit, not too excessive, so it can efficiently maintain its T & D network.