Va Rating Of Potential Transformer

The rated burden of a PT is a VA burden which must not be exceeded if the transformer is to operate with its rated accuracyThe rated burden is indicated on the nameplate.

Va rating of potential transformer. Calculate the VA rating using the formula VArating Vsecondary x I08 where Vsecondary is the secondary voltage of the transformer and the 08 accounts for the power factor of the load. VA ratings are also often used for transformers. Secondary voltage V s. To calculate the rating of the transformer for both single phase and three phase the load required to be fed and voltage at which load is to be fed must be known or should be calculated.

As losses are independent of the power factor of load the rating of the transformer is also independent of load and can be only decided based on losses. VA stands for volt-amperes. But Primary Voltages or High Voltages HV is 11000 V 11kV. Since the voltmeters and potential coils of other meters have high impedance a small current flows through the secondary of PT.

The error in secondary voltage of a Potential Transformer is defined as Ration Error Kn-R100R Where Kn Rated primary voltage Rated secondary voltage. A transformer with a 100 VA rating for instance can handle 100 volts at one ampere amp of current. Or take a larger VA transformer. To get this divide the VA rating by the voltage.

Sometimes the transformer can be rated by kVA kilo Volt-Amps or MVA Mega Volt-Amp. Since rating of transformer depends upon losses and losses depends upon V and I hence the rating of transformer depends upon VI which is also termed as VI rating. The rated voltage of the primary winding. Potential transformers PT or Voltage Transformers VT can be defined as devices used to step down voltage from high voltage typically used in transmission and distribution to a low voltage typically between 50-150V.

Also Secondary voltages or Low Voltages LV is 415 Volts. 75 VA 24 volts 3125 amps. Specify the phase arrangement. Due to this low load or burden on the PT the VA ratings of PTs are low and in the range of 50 to 200 VA.

Primary voltage V p. The kVA unit represents kilovolt-amperes or 1000 volt-amperes. Maximum output current is then VA rating divided by nominal output voltage. So using this formula a 75 VA rated 24 volt transformer has a maximum load of 3125 amps.

As per standards the rated voltage of a potential transformer is 110V. The transformer consumes the power regarding losses. The convention of using the volt-ampere to distinguish apparent power from real power is allowed by the SI standard. 1 Phase AC or 3 phase AC.

Enter the transformer rating and select the appropriate unit Enter the primary and secondary transformer voltages Click on the Calculate button to obtain the results. This is equal to 100 or 110 V for phasephase VTs. Therefore PT behaves as an ordinary two winding transformer operating on no load. Transformation Ratio of a Potential Transformer varies with the operating condition and therefore the voltage induced in the secondary of a Potential Transformer will also vary.

Hence the transformer is rated by the VA only. By using a PT voltage is reduced that can be safely handled by meter or relay circuits. The unit of apparent power is VA Volt-Amp. And Primary Current on High Voltage side is 525 Amperes.

250 VA 24 volts 1041 amp. The total deliverable apparent power is the rating of the transformer. So this circuit would be fused at a 3 amp maximum fuse. In a tep down transformer this will be the lower voltage.

Continuing with the example. The rating of the transformer also expressed in VA KVA and MVA depending on the size of transformer. VArating 208 x 6508 16900 volt-amperes or 169 kilovolt-amperes or 169 KVA. The power factor of load may be assumed to be 085.

In a step down transformer this will be the higher voltage. The rated voltage of the secondary voltage. Here is the rating of Transformer is 100kVA. A transformer with a 10 kVA rating is the same as a transformer with a 1000 VA rating and can handle 100 volts at 10 amps of current.

The rating of transformer is given in terms of its kVA HVLV voltage and phase rotation for three phase transformer. At the same time the windings of the transformer. This is because it is normal practice to earth one terminal of primary of the transformer. Burden of a Potential Transformer The burden is the total external volt-amp load on the secondary at rated secondary voltage.

Although we specify this voltage as line voltage but in actual case the secondary voltage is 1103 volts. In addition to this the voltage of source to should also be known. The foreseen application of the voltage transformer is used to determine the rated secondary voltage the accuracy power the accuracy class and the thermal power limit. Transformers with the same sized core usually have the same VA rating.

The tranformer rating in VA kVA or MVA. Thereby the rating of the transformer is in KVA and not in KW.