Three Phase Automatic Voltage Regulator

Variation of voltage can have detrimental effects on Utilities and their customers. To prevent customer complaints, loss of revenue due to sub-normal voltage, and increased costs due to higher line losses, FARADY has designed the SVR Voltage Regulator with you, “The Utilities”, in mind. With over 10 years of experience, FARADY has designed the most reliable regulator ever assembled.

Our expertise in both technology and service gives us an additional advantage in the custom engineering necessary for most 3-phase regulator applications. Many times refined and improved since, the SVR voltage regulator has proven its reliability and durability in the toughest environments. Unit construction, tough paint and side inspection door are just a few of the time-tested features of today’s SVR.


Ideally the distribution lines should to be able to keep the whole line of constant voltage,  but  in actual , the impedance of the distribution line will result in that the voltage  of end and terminal is not same( Figure 1). The actual voltage from the rated voltage of the circuit size is an important measure of power quality, also is a important guarantee of power supply reliability and voltage quality.



Since the line voltage can not be kept constant, when the actual voltage levels exceed the normal range of fluctuation of voltage allowed, it will seriously affect the normal use of the system and electrical equipment.

  • Electric power system:Low voltage will affect the power supply equipment output, reducing supply reliability, but also affect their own economic power, voltage drops particularly severe, even voltage collapse may occur, the frequency of loss and blackouts and other incidents
  • Electric equipment:Voltage quality have an impact on safe and economic operation of various types of equipment such as the asynchronous motor, for example, if the voltage decreases, the voltage will reduce torque so that the slip is increased, so that the stator and rotor current significantly increases, resulting in motor temperature liter rise, possibly even burning motor; on the contrary, when the voltage is too high, due to the excitation current and iron loss greatly increased, resulting in motor overheating, efficiency is reduced.
  • Low voltage will affect the use of incandescent lamps. Voltage 10% lower than the rated voltage, incandescent light flux is reduced by 30% higher voltage than the rated voltage of 10%, the lamp life is reduced by half.
    Low voltage will also affect the air conditioning running, cell phone charger, TV signal reception and other problems.
  • Power system losses:In conveying power certain time, the square of system losses and operating voltage, if the voltage decreases, the current increases and the loss, the loss will become larger system
Work Condition

(1)below 3000 meter;(special altitude can be customized)

(2)Work temperature: -25℃-65℃(special temperature can be customized)

(3)Monthly humidity less than(25℃)90% in 25℃

(4)Pollution class: III class

(5)Rating voltage :11/22/33kV or customized

(6)Rating capacity:500kVA~10000kVA


(8)Vector group:3phase 3 wire single winding star/delta

(9)tap change selector:9/11/13/17/27/32 position

(10)Cooling method:ONAN

(11)PT:10000/100V 50VA;

(12)CT:XXX/1A,2 meter method;

(13)third winding rating voltage:220V;

(14)regulator range:(-10%~+10%),(-5%~+15%),(0~+20%)(0~+30%)or customized

Operating Characteristics

TVR-line voltage regulator is a special design autotransformer with on-load tap changer, it can automatically “monitoring” and smoothly adjusts the output voltage, and also guarantee the output voltage within the voltage requirement. 27 taps regulation can meet every step 0.75% regulation accuracy. See blow figure 5


Figure 5:work principle


Figure 6. AVR Utility sample

In Figure 6, is an utility sample for a factory which require 400V electric power, but the power line is not stably in the summer because the load is 120% of rated capacity, so the power to the factory is lower than 360V, all the electric equipments in the factory can not use. After install Farady auto voltage regulator, it can adjust the power line voltage from 8038V to 11000V and keep it stable with 2% accuracy , so the power to factory can be keep at 400V(±8V accuracy).


○ Weights and dimensions are for reference only, and not for construction purposes. For exact dimensions, please contact Farady Electric co.,Ltd

Technical Chart (50Hz/60Hz)

Line voltagePower line capacityDimensionsTotal weight
kVkVALength (mm)Width (mm)Height (mm)kGs


Regulation range)



Regulation range)



Regulation range)


Function and features
1.6.1 High accurcy: 27 taps regulation in rated range
1.6.2 Long work life:Unique tap changer designed to avoid arcing ,the regulator can ensure the operating life of nearly a million times.
1.6.3 Maintenance-free:All sealing design,high IP protection degree,whole life maintenance-free
1.6.4 Flexible:Flexible mounting within the lines and substations, exit the operation and the opening and closing function when necessary.
1.6.5 Good function:Through  RS232  adapter of controller, SCADA distribution automation
1.6.6 Low loss:Design to maximize the reduction of iron loss , reduce load loss.
1.6.7 Economic:Economically effective voltage regulation circuit, a significant reduction in line losses and extended equipment life.
FK function features
1.7.1  Friendly user interface, can easily modify the settings and browse online data
1.7.2  Easy to set the voltage ,bandwidth, delay and offset voltage
1.7.3 Measurement of various data: load voltage, load current, apparent power, reactive power, power factor and so on.
1.7.4 Can be realized according to power flow direction, forward and reverse automatic voltage regulator (for ring network power supply), the completion of all the feature
1.7.5 Provide user RS232,RS485 data interface , can be long range remote control, telemetry, automation of distribution network
1.7.6 With a variety of communication protocols, it can be directly and master communication, no need to add RTU (FTU) devices.


Vacuum type on load tap changer

Regulator Vacuum type On load tap changer is of selector switch structure, which combines the functions of diverter and selector. The tap changer is mounted to the transformer tank cover by its head. When the tap changer is used without a change-over selector, the maximum operating positions available is 12, and it is up to 23 positions if with a change-over selector

  • Maintenance-free up to 100,000 tap-change operations with no time component.
  •  Exchange of the diverter switch insert after 1.2 million tap-change operations
  •  Intended for selected alternative insulating fluids
  •  Intended for operation in earthquake-prone areas
  •  Max current up to 600A
  •  Max voltage up to 145kV
  •  Max positions up to 23

Oil immersed type on load tap changer

Oil immersed type Changer is a typical combined-structure tap changer applicable in oil-immersed transformer, comprising of two major parts: diverter switch and tap selector. The OLTC is put in transformer oil tank and its diverter switch has a separate oil compartment from transformer tank, while tap selector, together with transformer windings, is completely laid inside the tank. OLTC’s installation is divided into two types – standard tank flange and bell-type flange.

  •  Electrical life arrives 50000 times.
  •  Mechanical life arrives 500000 times.
  •  Max current up to 400A
  •  Max voltage up to 35kV
  •  Max positions up to 23
  •  The contact resistance between joins not bigger than 500μΩ.
  •  Cheaper than Vacuum type tap changer.
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