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2022 ultimate guide to permanently eliminate voltage fluctuation & maximise productive uptime

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Severe voltage fluctuations can cause significant damage to critical electrical and electronic equipment, resulting in frequent interruptions to your crucial day-to-day operations — and even leading to substantial financial loss. 

Understanding the importance of a fully optimised voltage supply is key to the success of your systems reliability, your operational performance, and ultimately, your productive uptime. 

In this blog, we reveal the truth behind the causes and consequences of Voltage Fluctuations, and finally examine the most reliable and cost-effective ways to combat these pain points—once and for all.

What is voltage fluctuation? 

Voltage fluctuations are changes or swings in the steady-state voltage above or below the designated input range for an equipment. Fluctuations include both voltage sags and swells.

Known as a continuous change in voltage, or an erratic response of a power system reacting to fast changing loads, these ‘inherent’ power problems are detrimental to most electrical loads — silently crippling your electrical systems’ operational efficiency. 

These graphs show fluctuating voltage waveforms that exhibits variations in magnitude due to voltage fluctuations.
These graphs show fluctuating voltage waveforms that exhibits variations in magnitude due to voltage fluctuations.

Figure 1 gives a general representation of a voltage waveform when there is a periodic voltage fluctuation. The change in voltage envelope is dependent on the type of load and the duration for which it is switched on.

Figure 2 illustrates voltage fluctuations on an unbalanced voltage situation on Line 1, Line 2, and Line 3.

Voltage fluctuations cause significant damage to critical sensitive loads — compromising essential day-to-day operations in your business.

Severely harmful voltage irregularities can set your operations up for failure: 

  •  Your electrical loads begin experiencing frequent equipment malfunction;
  • Drastically decreasing equipment healthy lifespan;
  • And in extreme cases, expensive emergency repairs, or unplanned downtime.

To effectively tackle voltage fluctuations, we need to find out why voltage fluctuations happen. 

Why do voltage fluctuations happen?

Voltage fluctuation happens during extensive usage of equipment with higher load. Whenever current passes through a resistance, a voltage drop occurs across that resistance.

The amount of the voltage change is given by Ohm’s Law: V=IR


V = The voltage value

I = The current through the circuit in Amperes (A)

R = The total resistance of the circuit

Power Quality Measurement of a Commercial Building across 1 week
Power quality measurement of a commercial building across one week

Figure 3 shows how a sudden load change during the day and night dramatically affects voltage stability. 

Voltage fluctuations occur due to rapid or cyclic voltage change. These voltage irregularities can be repetitive or random variations of the voltage envelope due to sudden changes in the real, reactive power drawn by load equipment.

What other factors contribute to voltage fluctuations?

Poor electrical supply

Using a low-capacity transmitter to transfer power from the main supply can cause improper flow of electricity. Faulty electrical equipment also draws more electric current than usual—resulting in voltage fluctuations in your electrical supply. 

High inrush current

Concurrently or repeatedly starting (and restarting) motors can cause voltage change and rapid voltage fluctuations. Connecting too much equipment, like motors, contactors, relays, and breaker operations to the same circuit also causes serious voltage irregularities in your electrical systems. 

Poor wiring

Other causes of voltage fluctuation include poor wiring, corroded, and loose connections. Often identified by the flickering of lights, in extreme cases, a loose connection can cause electric shocks from metal appliances and surfaces in your home. 

Natural causes

Voltage fluctuations are also caused by lightning, strong winds, trees or animals touching the power lines, and even accidents involving these power lines. 

How severe can voltage fluctuations be on your electrical system?

Harmful voltage irregularities also cause electrical malfunctions, equipment failures, and even disruptions to entire facilities. Such outcomes often result in expensive emergency repairs and replacement costs.

Both over and under voltage levels gradually lead to several undesirable reactions in your electrical systems—such as overheating, and higher energy bills.

As a result, your equipment is prone to breakdowns. Your wirings might also lose strength, and possibly trigger short circuits — compromising fire safety in your workplace.  

Since “Prevention is better than cure”…

How to eliminate voltage fluctuations

It is important to first diagnose the problem and find out the main causes. Electrical Consultants rely on two methods to overcome unpredictable voltage change:

  • Option A: Conventional method
    Reducing voltage fluctuations with preventive measures. 
  • Option B: Adaptive & cost-effective solution
    Delivering perfect power protection that safeguards systems reliability, operational efficiency, and productive uptime.

Option A: Conventional method

Increasing fault level at point of connection

Done by strengthening the system or reconnecting the offending load at a higher voltage level.

Decrease reactive power flow throughout the network due to the load

Achieved by using a Static Var Compensator (SVC) to reduce voltage fluctuations.

Strengthening the network reactive power consumption

A greater number of smaller capacitor banks distributed throughout a system allows for finer tuning of reactive power requirements.

Option B: Adaptive & cost-effective solution

Recognised as a long-term and cost-effective answer to disastrous voltage anomalies, Automatic Voltage Regulators (AVR) are now highly adopted by Government Agencies and National Grid Operators as an advantageous approach to maximise uptime, and fortify mission-critical applications.

Automatic Voltage Regulators (AVR)

 Key advantages of an AVR:

  • Safeguards high value assets from harmful voltage irregularities.
  • Delivers absolute voltage stability to facility equipment and sensitive electronics.
  • Prolongs essential loads’ healthy lifespan.
  • Significantly reduces excessive preventive maintenance efforts.
  • Achieves substantial passive savings on decreased energy consumption.  
  • Effectively maximises precious productive uptime.

Because of its versatility and high reliability, Automatic Voltage Regulators (AVR) are now the preferred choice of protection for forward-thinking engineers. But how exactly do they function?

How does an automatic voltage regulator work? 

The AVR consists of a few essential components to ensure continuous, autonomous, and automatic operations:  

  1. Servo Amplifier
    That continuously detects any voltage change on the incoming.
  2. Buck-Boost Transformer
    To compensate for voltage change on the incoming supply.
  3. Variable Transformer or Variac
    Allows fine adjustments to the output voltage.

For the AVR to automatically regulate and maintain a balanced voltage (of your desired output level), the AVR first detects excessive input voltage change (overvoltage or undervoltage).

Using a Buck-Boost transformer, the voltage is then ‘compensated’ to bring up or down the voltage levels where necessary.

Finally, a variable transformer makes fine adjustments to ensure complete voltage stabilisation — providing highly accurate voltage delivery (up to ±0.5% accuracy) straight to the connected load.

This constant and automatic process guarantees your operations with optimum voltage levels, eliminating all forms of voltage fluctuations—with no compromise.

Features of an AVR

With various types of Automatic Voltage Regulators designed for unique applications, here are the key features to consider when researching for your ideal model.

1. Precise output voltage regulation

For critical applications, pay close attention to the Output Voltage Accuracy. In an AVR’s specification, the Output Voltage Accuracy ranges from an extra tight regulation of ±0.5%, up to ±10% (depending on the type and built quality). For ±0.5% Accuracy, this means that the output voltage will not exceed more or less than 0.5% of your set output voltage e.g. 230V.

The lower the Output Voltage Accuracy, the higher the stability and quality of your voltage supply.

2) Step-less voltage regulation

According to industry practises, for applications consisting of high-value electronics, the preferred method of voltage control is one that delivers stepless voltage regulation.

Typically provided by Servo AVRs (Servo Electronic Automatic Voltage Regulators), this method delivers a smooth and seamless voltage stabilisation that provides adequate protection for sensitive loads.

3) Virtually maintenance-free

For applications located at remote sites, inaccessible to reliability teams, or require a more maintenance-free approach to their operations — consider AVRs that are Virtually Maintenance-free.

In a Magnetic Induction AVR (Magnetic Induction Automatic Voltage Regulator), the fundamental voltage control philosophy is based on a Stator and Rotor operation. To perform reliably, the magnetic induction AVR relies on brushless technology (no carbon brush) to efficiently regulate erratic voltages in a contactless fashion.  

Because of its near-zero wear and tear during voltage stabilising operations, the magnetic induction AVR is considered a ‘Plug-and-Forget’ solution with the most robust power protection for most industrial and commercial applications.


Regardless what method you choose to eliminate voltage fluctuations, there are many options available that will help you fortify your systems reliability, safeguard your equipment readiness, and maximise your precious productive uptime.

Ultimately, what’s most important is that you find a solution that is ideal for your unique application, and is both on point, and on budget.

Want to achieve the absolute best voltage optimisation results in your electrical system?  

Visit to discover our complete range of time-tested Automatic Voltage Regulating Solutions.

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