Analysis of Transformer Energy Saving
Transformer is one of the main equipments in power transmission and transformation system. Although its efficiency is high (large transformer efficiency is higher than 99.5%, small transformer is also above 98%), but its overall capacity is large (under normal circumstances The total capacity of the transformer is 5 to 7 times the power generation capacity. Combined with more transformation stages in the transmission and distribution system, the loss can account for 17% of the total line loss. Although small and medium-sized distribution transformers have a small capacity, they are numerous. China requires the promotion of the use of low-energy-consumption transformers and the transformation of high-energy-consumption transformers in a relatively short period of time. This is an effective way to tap potential energy and increase economic efficiency.
Transformer energy-saving transformation of specific methods include: derating, capacity, capacity expansion and capacity adjustment four methods.
(1) Winding reforming method: change the demagnetization method for high and low voltage windings; change the high and low voltage winding capacity adjustment method; change the high and low voltage winding drop and capacity adjustment method; change the high and low voltage winding capacity preservation method; change the high and low voltage windings Quality law; change the high and low voltage winding expansion method.
(2) iron core restructuring method: exchange all iron core method; exchange part of the iron core method; exchange part of the core method; exchange all yoke method; exchange part of the yoke method; increase and decrease the column column method; increase and decrease the diameter of the core column; Monolithic overlapping iron core method; iron core silicon steel overlap method; iron core silicon steel reinsertion method.
(3) Winding and iron core revamping method: Completely changing the winding and core dilatation method; Completely changing the winding and core holding capacity method; Completely changing the winding and core derating method.
After energy-saving transformation of transformers, technical indicators and requirements should meet the requirements of relevant state regulations:
(1) The no-load loss of the transformer is reduced by 45% to 55% compared with that before the reform, which is better than the data of the JBl300-73 standard I (cold-rolled silicon steel sheet) and reaches the data of the S7 or SL7 low-loss transformer;
(2) The no-load current is reduced by about 70% before reforming;
(3) The loss of no-load short circuit is in accordance with the national standard or related regulations;
(4) Impedance pressure drop is controlled at 3.6% to 5.5% (3 to 10 kV, 30 to 1 600 kVA) and 6% to 7.7% (35 kV, 50 to 1 600 kVA).