|Secondary Voltage||1 Amp or 5 Amp|
|Accuracy Class||0.2, 0.5|
Backed by rich industry experiences, we are highly engaged in offering a premium quality range of Residual Voltage Transformer. Owing to its hassle free operations and low maintenance, the offered transformer is highly demanded among our esteemed clients. In adherence to the set industry standards, the provided transformer is manufactured by our highly experienced professionals using the modern technology. Further, our valuable clients can avail this transformer from us at industry leading prices.
We are one of the leading manufacturer of RVT of any class, ratio, burden. Our RVT are quality product as per IS / IEC. We can manufacture RVT of all types up to 33 KV voltage class as per customer requirement on most competitive prices. Residual voltage transformer is used to detect unbalanced voltage in three phase system & to supply voltage to directional earth – fault relay. For directional earth - fault relay. It is necessary that the voltage applied to the voltage coil of the relay corresponds in phase to that of the current in current coil such voltage will be the residual voltage of the system & will be the phasor sum of the three line - to - earth voltages. Residual voltage can be achieved by connecting secondaries of three single phase V.T. Connected in three different phases, in open delta fashion. It is, however, economical to use three phase V.T. Instead of three Nos. Single phase R.V.T. Suitable up to 33 KV system voltage. In normal three phase three limb V.T. When one phase experiences earth fault. The resultant flux due to two healthy lines returns through transformer limb of faulty line, including a heavy short circuit current in the WDG. On the limb. Also voltage induced in secondary open - delta WDG. Is not true residual voltage. To overcome this difficulty two separate limbs are provided in the magnetic circuit of three phase voltage transformer to form five limb voltage transformer.
With Three Cases:
Under healthy condition all three phases will be balanced & hence residual voltage ‘VR’ will be zero. In system with unearthed neutral, if there is earth fault on one line, neutral of V.T. Will be shifted, such that each healthy phase WDG. Will have line - to - line voltage with 60 phase difference. The resultant open - delta voltage shall be therefore, the resultant open - delta voltage shall be therefore, three times phase voltage. (VR = 3 VS). In solidly earthed system, neutral of the V.T. Does not get shifted due to earth - fault on one line. Therefore, the resultant open - delta residual voltage remains phase voltage only (VR = VS). Primary WDG. Of R.V.T. Is connected in star. The secondary WDG. Is connected in open - delta. Some - times additional secondary WDG. Is provided in R.V.T. For measuring purpose & is connected in star. Ratio of R.V.T. For measuring purpose generally specified. As line - to line - primary voltage to open - delta residual voltage. IT, therefore becomes necessary to mention system neutral condition so as to select phase voltage of the open - delta WDG. Correctly. When R.V.T. Are used along with capacitor bank, capacitor bank gets discharged through primary WDG.