Techniques for controlling voltage in power systems

Techniques for controlling voltage in power systems

Voltage control plays a pivotal function in retaining the stability and reliability of the electrical network. Various techniques are employed to alter and preserve the desired voltage ranges, ensuring the efficient operation of the electricity machine. This complete blog explores the special strategies of multiple voltage control methods, with a focus on the mechanisms and technology used to control voltages successfully.

Significance of Voltage Control in Power Systems

Effective voltage management within energy structures is paramount because of its profound effect on purchasers and electrical devices. Fluctuations in voltage stemming from changes in system load need to be cautiously regulated to save you from adverse outcomes. Maintaining these voltage versions within designated limits is vital for the following motives: 

Precarious Lighting Load

  • Voltage fluctuations significantly influence the lighting load of a lamp.
  • A mere 6% reduction in the provided voltage to an incandescent lamp can bring about a huge 20% lower in illuminating energy. 
  • Conversely, a 6% voltage increase can lead to a 50% reduction in the lamp's lifespan, primarily due to accelerated filament degradation.

Implications for Power Loads with Induction Motors

  • Power loads, particularly those in the induction motors, exhibit sensitivity to voltage changes.
  • Excessive voltage can also set off erratic motor operation, inflicting a saturated magnetic circuit, heightened magnetising currents, heating, and diminished energy output.
  • Conversely, low-voltage stages can significantly decrease the starting torque of the motor.

Transformer Heating Concerns

  • Wide voltage variations contribute to the excessive heating of distribution transformers.
  • This excess heating can significantly reduce the transformers' ratings, therefore impacting their overall efficiency and reliability.

From the above discussion, it becomes evident that minimising voltage variations in energy systems is critical for turning in dependable providers to customers. With the developing incidence of larger interconnected structures, the incorporation of methods of voltage control in distribution systems is not just beneficial but vital. These strategies play a pivotal function in ensuring stable voltage ranges, safeguarding the efficiency and durability of electrical gadgets and structures, and, in the end, providing a steady and reliable power supply to purchasers.

What are the different methods used for voltage control?

Voltage can be controlled in multiple ways. Here are some of the best voltage control methods known to mankind. 

Read Also: Effective Ways of Protecting Your House From Voltage Surge

Static VAR System (SVS)

The Static VAR System (SVS) is one kind of Flexible AC Transmission System (FACTS) technology hired to decorate the stability and manipulation of electricity systems. An essential part of SVS is the Static VAR Compensator (SVC), which is specially designed to alter reactive power in the machine. 

When the voltage surpasses the predetermined reference value, the SVC absorbs reactive power. Conversely, it injects reactive electricity when the voltage falls underneath the reference fee. This dynamic operation aids in retaining voltage in the appropriate variety, contributing to heightened stability inside the energy machine.

In the assessment of traditional circuit breakers, SVCs make use of thyristors as switching devices. Thyristors, semiconductor gadgets with fast on-off capabilities, facilitate swift and specific manipulation of reactive power. Leveraging thyristor switching gives blessings which include quicker response to strength system adjustments. Moreover, the transient-unfastened operation carried out via thyristor switching mitigates the threat of harm to electricity gadget additives.

Tap Changing Transformers

The regulation of voltage in transmission and distribution systems is normally done via the usage of tap-changing transformers. In this technique, the road voltage is adjusted by means of altering the secondary electromotive force (EMF) of the transformer through the variation of the range of secondary turns. The secondary voltage of a transformer is immediately proportional to the number of secondary turns, bearing in mind the adjustment of the secondary voltage by converting the turn ratio of the transformer. Tappings supplied on the winding facilitate the variation of the secondary quantity of turns. There are two kinds of faucet-changing transformers: off-load tap-converting transformers and on-load tap-changing transformers.

Off-load faucet-changing transformers involve disconnecting the transformer from the energy supply earlier than adjusting the faucet. While those transformers are relatively cost-powerful, a significant drawback is the interruption of strength delivery at some stage in the faucet-changing procedure.

On-load tap-changing transformers, however, are preferred in contemporary power systems wherein the continuity of the energy supply is essential. Unlike off-load transformers, on-load tap-converting transformers permit voltage management without interrupting the power delivery. This makes them favourable for packages where uninterrupted electricity is crucial.

Induction Voltage Regulators

An induction regulator capabilities as an electrical device, equivalent to an induction motor with a fantastic difference—the rotor is not approved to rotate continuously. The rotor of the induction regulator accommodates the primary (excitation) winding, which is related in parallel to the delivery voltage. Meanwhile, the desk-bound secondary winding is hooked up in collection with the road that calls for law. From an electrical perspective, whether the number one or secondary winding is rotating is inconsequential. The significance of voltage within the secondary winding is contingent upon its role relative to the primary winding. Consequently, the adjustment of the secondary voltage is performed by rotating the primary winding.

In these advanced times, induction voltage regulators have been employed to alter the voltage of electrical networks. However, they were supplanted by means of faucet-changing transformers in present-day packages.

Shunt Reactors

Deployed at each of the sending and receiving ends of long Extra High Voltage (EHV) and Ultra High Voltage (UHV) transmission traces, shunt reactors are pivotal in voltage control. These reactors feature as inductive elements, compensating for the road capacitance, especially below light hundreds. The Ferranti impact, which leads to a better receiving stop voltage while the transmission line isn't always closely loaded, is mitigated through the strategic use of shunt reactors. This guarantees that the voltage remains inside the preferred range, improving the general stability of the energy machine.

Shunt Capacitors

Shunt capacitors serve as vital components for voltage management, particularly at receiving give-up substations or in proximity to commercial masses. Many industrial hundreds exhibit inductive traits, leading to a lagging strength thing. Shunt capacitors deal with this trouble by compensating for the inductive reactance, thereby lowering the IXL drop. By strategically deploying shunt capacitors, the power gadget can successfully control line voltage, ensuring ultimate overall performance and mitigating the effect of inductive loads on voltage degrees.

Synchronous Condenser

A synchronous condenser, operating as an over-excited synchronous motor on no load, acts as a synchronous segment modifier. Positioned close to the burden quit, the synchronous condenser has the functionality to inject or take in reactive electricity, contributing to improved voltage profiles. By actively collaborating inside the control of reactive power, synchronous condensers play a crucial function in voltage manipulation inside the electricity machine. Their ability to pleasant-song reactive energy tiers ensures that the voltage stays stable and within the desired parameters.

Read Also: Know More About Voltage Surge Protector


Power systems need voltage control to be operated in a stable and efficient manner. Therefore, techniques such as reactive-power compensation, tap-changing transformers and voltage regulators are used. These techniques keep the system's voltage levels at ideal place, improve overall system reliability, and better control the distribution of electrical load.

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