HET 125kVA/3.5kV,2kV Exciter Transformer

Mode: HET 125kVA/3.5kV,2kV
Rated capacitance: 125kVA
Single phase
Cooling methods: ONAN
Rated voltage:  LV voltage: 0.6kV    HV voltage: 2, 3.5kV        
LV current: 208A     HV current: 35A
Rated frequency: 50Hz
Impedance voltage:<4%
Shielding methods: Set electrostatic shield layer between HV windings.
Partial discharge: ≤2pC under rated voltage.
Exciter transformer protection: equip piezoresistor for each HV output, exciter transformer’s input and output terminal connects with the ground via zinc oxide arrester, this methods can protect the operator and the equipment itself when test object breakdown. Over-current capability: working 1 hour under 160% IH, no damage to reactor winding . Working time and temperature: continuous working under rated current; one hour on and one hour off under 160% rated current, ; not surpass 8 cycle per day; winding temperature raise not surpass 65K, oil temperature raise less than 55K Exciter transformer protection: equip piezoresistor for each HV output, exciter transformer’s input and output terminal connects with the ground via zinc oxide arrester, this methods can protect the operator and the equipment itself when test object breakdown. Structure: steel housing, HV bushing equips on the oil tank, equips wheels, movable, oil tank is shell-type, lead out the Low voltage with porcelain bushing. Each terminal is lead out by relative voltage grade bushing. HV bushing lead wire go through isovolumetric capacitance core, exterminable insulation is fiber glass bushing. Bushing has corona rings. Oil tank has oil conservator to make sure the capacitance core in the oil. HV bushing can guarantee 5kV corona free. Exciter transformer insulation characteristic: Exciter transformer insulation level will determine transformer’s safety work and insulation ageing speed. To guarantee no flashover- which coming from external, electric potential raise and cause damage to the main insulation and minor insulation. We will also set insulation layer between HV windings and turn-to-turn. Winding is cylinder type. Capacitance is  determin by the winding’s area. When design, we’d try our best to make sure the top and bottom has same area, and compensate with electrostatic shield to improve the initial voltage distribution. Winding skeleton is made of compound insulation tube: can get down partial discharge and shielding the iron coil.

Principle Diagram: