insulation tester (Megger) can used to checked the short circuit on HV side.
HI POT tester is also a means to checked the shot circuit in HV cable.
Lower voltages are required if connected to the low voltage side. The testing facility may not have a gen set large enough to test from the high voltage side.
In OC test , the equipments are connected in LV side since we need to get rated voltage . if it is cinnected in HV side the value of voltage will be less and current wil be more.Hence the ordinary instruments cannot measure this value of current
This is because of two reasons: 1. Primarily because SC test is performed at rated Current(as we calculate series parameters-leakage impedance-in SC test). As the rated current on hv side is much less than lv side(VI = constant), so the rated hv side current is easily achieved(compared to lv side). Vice-versa is true for Open circuit test. 2. Also because we cannot short-circuit hv side, as, if we short-circuit hv side, V of hv side essentially falls to zero and since VI(KVA power)=constant, so the hv current will be very high(compared to low rated current on hv side), and will burn the winding. When short-circuiting lv side, the current also increases but this increase does not burn winding due to low rated V and high rated I (You can consider the example of 220/11V)on lv side. So,SC test is performed on hv side while shorting the lv side. Also SC test can be performed on either sides for small transformer rating. The above care must be taken for big transformer(High KVA rating)..
magnetic core balance test is used to find out the flux distribution. It can conduct either in HV side or LV side. In HV side, applying voltage between 2 phases and measuring the voltage across other phase.(eg.applying b/w U&V, and voltage b/w V&W , W&U measuring.) In LV side, applying voltage b/w any phase....and measuring voltage across other phases. Result: sum of measured voltage will be equal to applied voltage.
It is carried out by tap-changing on the HV side of the transformer. The number of turns on the winding is increased or decreased by a number of turns to make the secoondary voltage take the right value. Tap-changing is done on the HV side because each turn is a smaller percentage of the voltage, which permits finer adjustment.
Lower voltages are required if connected to the low voltage side. The testing facility may not have a gen set large enough to test from the high voltage side.
The keyword "hv kt" likely stands for "have kept."
in hv side, current will be less; so if we vary the rheostate, than thetre is less arcing with respect to lv side, so we always put the tap changer in hv side.
In OC test , the equipments are connected in LV side since we need to get rated voltage . if it is cinnected in HV side the value of voltage will be less and current wil be more.Hence the ordinary instruments cannot measure this value of current
This is because of two reasons: 1. Primarily because SC test is performed at rated Current(as we calculate series parameters-leakage impedance-in SC test). As the rated current on hv side is much less than lv side(VI = constant), so the rated hv side current is easily achieved(compared to lv side). Vice-versa is true for Open circuit test. 2. Also because we cannot short-circuit hv side, as, if we short-circuit hv side, V of hv side essentially falls to zero and since VI(KVA power)=constant, so the hv current will be very high(compared to low rated current on hv side), and will burn the winding. When short-circuiting lv side, the current also increases but this increase does not burn winding due to low rated V and high rated I (You can consider the example of 220/11V)on lv side. So,SC test is performed on hv side while shorting the lv side. Also SC test can be performed on either sides for small transformer rating. The above care must be taken for big transformer(High KVA rating)..
To ascertain the life of insulation, or effectiveness of the insulation (HV to LV, HV to earth and LV to earth) of the transformer
magnetic core balance test is used to find out the flux distribution. It can conduct either in HV side or LV side. In HV side, applying voltage between 2 phases and measuring the voltage across other phase.(eg.applying b/w U&V, and voltage b/w V&W , W&U measuring.) In LV side, applying voltage b/w any phase....and measuring voltage across other phases. Result: sum of measured voltage will be equal to applied voltage.
generally open circuit test is performed on the low voltage side.....not on high voltage side.... becuase on low voltage side, we can apply that low voltage very easily ( i.e with a less amount of source is required)... whereas on high voltage side, we need a large power source in order to apply full voltage... in short circuit test, we will test on high voltage side by keeping Low voltage side being short circuit.because high voltage side needs less current source than low voltage side....
Open circuit test on a transformer is usually performed to measure the IRON losses.Iron losses are produced due to eddy current and hysteresis losses. In open circuit test, the LV side, generaly the secondary winding, is kept open and the HV side, generaly the primary winding is fed with the rated voltage and frequency. The rated voltage is applied in order to setup normal flux in the transformer, which in return further produces the normal iron losses at rated voltage. the wattmeter connected at the primary side will show the power consumed due to iron losses. this calculation further utilized for determing the efficiency of transformer.
During maintenance following test to be done : transformer oil test ht / lv side insulation test also hv to lt oil temperature trip / alarm winding temperature trip / alarm bukkhoze relay trip / alarm PRV setting to ok MOG trip / alarm etc.
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To convert high voltage (HV) amps to low voltage (LV) amps, you can use the formula: HV amps = LV amps x (LV voltage / HV voltage). By rearranging the formula, you can calculate LV amps by dividing HV amps by the ratio of HV voltage to LV voltage.