Q1：What are the typical application scenarios of 500kVA three-phase oil immersed transformers?
*Power distribution for small and medium-sized factories;
*Electricity supply for commercial buildings, hospitals, or schools;
*Voltage conversion of rural power grids or community distribution systems;
*Power distribution at temporary construction sites.
Q2：What are the common configurations for the rated input/output voltage of a 500KVA transformer?
*High voltage side: 11kV (domestic distribution standard);
*Low voltage side: 400V (three-phase four wire system, line voltage 400V/phase voltage 230V);
Q3：How to calculate the rated current of a 500KVA transformer?
*High voltage side: I=500kV/11kV/√3=26.24A
*Low voltage side: I=500kV/0.4kV/√3=721.7A
Q4：What are the requirements for the surrounding environment during the installation of a 500KVA transformer?
*Good ventilation, keep away from flammable and explosive materials;
*The basic platform requires horizontal load-bearing capacity (with an oil content of approximately 200kg);
*Reserved heat dissipation space (with a side distance of ≥ 0.8 meters from the wall and no obstacles at the top);
*Outdoor installation requires the installation of rain covers or fences.
Q5：What is the overload capacity of a 500kVA transformer?
*Short term overload (such as within 2 hours) can reach 150% load (copper coil);
*Long term overload will accelerate insulation aging, and it is necessary to avoid operating beyond the rated capacity.
Q6：What are the key points to pay attention to in the daily maintenance of a 500KVA transformer?
*Oil level check: The oil level gauge of the oil pillow should be within the marked range;
*Oil temperature monitoring: During normal operation, the top oil temperature is ≤ 65 ° C;
*Leakage inspection: Check whether the welds and gaskets of the fuel tank are leaking oil;
*Regular tests: insulation oil withstand voltage test, winding DC resistance measurement (once a year).
Q7：How to determine if the insulation oil needs to be replaced for a 500KVA transformer?
*Breakdown voltage: below 30kV (new oil standard ≥ 35kV);
*Excessive acid value:> 0.1mg KOH/g
*High moisture content:> 20ppm
*The oil color is dark black or contains carbide particles (needs to be filtered or replaced).
Q8：Possible causes and solutions for abnormal
temperature rise of 8.500KVA transformer?
*Reason: Overload, blocked radiator, oil circulation failure, internal winding short circuit;
*Solution: Immediately reduce the load and check the load; Clean the radiator or repair the cooling system; Suspend maintenance due to internal malfunction.
Q9：What protective devices must be configured for a 500KVA transformer?
*High voltage side: drop out fuse or circuit breaker (overcurrent protection);
*Low voltage side: air switch (short circuit protection);
*Body protection: gas relay, pressure reducing valve, thermometer;
*System protection: lightning arrester (lightning protection), grounding device (grounding resistance ≤ 4 Ω).
Q10：How to choose the energy efficiency level of a 500KVA transformer when purchasing?
*Standard: According to local national energy efficiency regulations or customer requirements
*Example: The latest energy-efficient 500kVA oil immersed transformer in Europe has a no-load loss of 459W and a load loss of 3900W; Energy efficiency>99.46%
