Three problems to be considered in the determination of the main junction plan of building electrical installation

For advanced hotels, air conditioning refrigeration load accounts for about 38%, and the seasonal variation of these loads. In summer, the peak load, the winter is empty load, the transition season for light load. Therefore, this feature should be taken into account in determining the main wiring scheme and the selection of electrical equipment. Therefore, in the main junction line should be supplied by a separate transformer (as shown in Figure 1-2-3), to reduce the no-load loss of transformer. Due to the change of the air conditioning load, in the choice of transformer capacity, should be fitted with air conditioning design professionals, according to the changes, select the appropriate combination of transformer capacity, so that the transformer is in the state of the economy. Although the annual load curve of elevator and lighting load changed little, the daily load curve changed greatly. Elevator to work or work for the peak load, during the work period for normal operation, after work or at night for light load. Lighting load is light load during the day or night, while at 6-11 p.m.. As a result, the voltage fluctuation caused by load changes, the normal operation and service life of the equipment are affected. Therefore, in the selection of lighting and elevator power supply transformer, should be used with automatic voltage regulating device of the transformer, so that the output voltage of the transformer can vary with the load, to ensure the appropriate voltage level. On the protection of high voltage side of the transformer, the circuit breaker is often used in our country, while the foreign single transformer and the capacity of 30-50% is usually used when the fuse. Because the price is only a fuse circuit breaker, simple structure, convenient installation, breaking process without moving mechanical parts, but caused by the electric arc melting in the melt, in quartz sand under the action of the arc to disconnect the circuit, time for inverse time current characteristics, because of omitting the cumbersome relay protection circuit the system is greatly simplified, the construction is convenient. In foreign countries, the ratio of circuit breaker and load switch is 1:5, while China is 10:1.