8+FAQ About the Voltage Transformer

As you know, ever since the pandemic, electricity consumption has spiked to a high scale, which led voltage transformers to be in high demand including various types of voltage transformers like high voltage transformers.

This goes the same for voltage transformer converters as well that is capable of supporting voltage transformers 220v to 110v.

In this article, DAELIM, an expert voltage transformer manufacturer, will provide you with the necessary information needed for you to formulate a purchase decision. 

But before going through an in-depth discussion about the specifications of voltage transformers, it is important to know the fundamentals first.

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What is a Voltage Transformer

So, what is a voltage transformer?

A voltage transformer or also known as “V.T” is a type of transformer that belongs to the category of potential transformers, which are transformers that have a parallel-type of connections of an instrument transformer.

Voltage transformers are specifically designed to present a negligible load to the supply that is measured for the purpose of having an accurate voltage ratio and phase relationship that is accurate to the secondary metering that it is associated with.

Voltage Transformer
Voltage Transformer

What are Instrument Transformers?

Speaking of instrument transformers, what are they?

Instrument transformers are basically transformers that are commonly used in an A.C or alternating current system for measuring electrical quantities like voltage, energy, current, power factor, frequency, and other elements. 

Moreover, they are also used as protective relays for the protection of power systems.

The main function of instrument transformers is to step down the alternating current system voltage and current. 

This means that the voltage and current levels of power systems are very high. 

Furthermore, this would ve hard and expensive to design the measuring instruments needed for 5A and 110V.

When it comes to the measurement of large quantities like this electrical device, it can still operate with the help of using instrument transformers since these only have small measuring instruments, making it in high demand as well for modern power systems.

Voltage Transformer Ratio

When it comes to the voltage transformer’s ratio, the P.T is usually determined by its voltage ratio from its primary to the secondary.

For instance, a 600:120 P.T ratio will give you an output of 120 volts when 600 volts are being pushed through across the primary winding.

On the other hand, the standard secondary voltage ratings are around 120 volts and 70 volts, which means that they are perfectly compatible with standard measuring instruments.

The PT is typically described by its voltage ratio from primary to secondary.

A 600:120 PT will provide an output voltage of 120 volts when 600 volts are impressed across its primary winding.

Standard secondary voltage ratings are 120 volts and 70 volts, compatible with standard measuring instruments.

Accuracy Rating

For its accuracy and burden, it is normally stated as a combined parameter because of is dependent on one another.

A meter P.T’s style is basically designed with smaller cores and V.A capacities like power transformers.

This makes the metering P.Ts saturate at lower secondary voltage outputs that secure sensitive connected metering devices from harm and damage large voltage spikes that are commonly caused by grid disturbances.

Voltage P.Ts with a rating of 0.3W, 0.6x will indicate with up to W load or commonly rated at 12.5 watts of secondary burden to the secondary current that is ranged between 0.3 percent error of parallelogram in terms of the accuracy diagram that incorporates both phase angles and ratio errors.

The same strategy will apply for X load or 25 watts rating.

However, this excludes 0.6% accuracy to the parallelogram.

Voltage Transformer Markings

There are transformer windings out there that connect wires of many types of voltage transformers.

There are transformer windings (primary) that are usually at high voltages as well.

They can be labeled as H1 or H2, but H0 can also be used if it is to be grounded.

Moreover, X1 and X2 are also common terminologies and X3 tap can be present as well.

In terms of isolating the second winding Y1, Y2, and Y3 and for third, Z1, Z2, and Z3, these can be available on the same voltage transformer.

The primary can also be a connected phase to the found or phase to phase.

Furthermore, the secondary is commonly grounded on one terminal to prevent capacitive induction from causing damage to low-voltage equipment and for the safety of the people within the vicinity as well.

Different Types of Voltage Transformers

Like transformers in general, there are many types of voltage transformers as well, and below are the categorized groups of voltage transformers.

To begin with, there are three primary types of voltage transformers, namely: electromagnetic, capacitor, and optical.

Capacitor Voltage Transformer

A capacitor voltage transformer or also known as C.V.T is a type of voltage transformer that is commonly used in power systems for stepping down extra-high voltage signals that provide low-voltage signals, and this involves metering or operating a protective relay.

In simpler terms, this electrical device is consists of three parts which are two capacitors across which the transmission line will signal it off as split.

This involves an inductive element that is for tuning the device into the line frequency, and a voltage transformer to isolate and step down the voltage for metering devices or protective relays.

When it comes to the tuning of the divider into the line of frequency, this will make the overall division ratio less sensitive to changes in the burden that is connected to a meter or protected divides.

A capacitor voltage transformer or capacitor C is constructed as a stack of smaller capacitors that are connected in a form of a series.

This means that it will provide a large voltage drop across the C section, and there will be a relatively small voltage drop in the same section as well.

The majority of voltage drop is on Capacitor C because this reduces the required insulation level of the voltage transformer.

Meaning, this will result in a more Capacitor voltage transformer which is more economical than wound voltage transformers that are under high voltages, specifically over 100 kV (kilovolt-amperes).

This goes to show that the latter will require more windings and materials

Furthermore, C.V.Ts are also useful interns of communication systems because the combination of C.V.TS with wave traps is utilized for filtering high-frequency communication signals from power frequency.

This will also form a carrier communication network all throughout the transmission network to link between substations.

Basically, the C.V.T. is installed at a point after a lightning arrestor and before a wave trap for the best allocation of the electrical device.

What is a Voltage Transformer For?

A voltage transformer is an electrical device that is capable of converting energy from one form to another.

Voltage transformers are also used to monitor alternating currents or DC currents by measuring the voltage directly or through a voltage transformer.

Voltage transformers have a parallel connection type of an instrument transformer as well.

This means that voltage and potential transformers can be utilized with voltmeters for voltage measurements.

Another option is using it with current transformers which act as wattmeter or watt-hour meter measurements.

Furthermore, voltage transformers and potential transformers are also used to operate protective relays and devices, and as well as other applications.

What is the Difference between a Voltage Transformer and a Current Transformer?

Voltage transformers are commonly mistaken as current transformers and vice-versa, this means that transformers are capable of converting the high value of current into low value.

On the other hand, potential or voltage transformers convert the high values of voltages into low voltage levels.

How Does a Voltage Transformer Work?

As you know, transformers are electrical devices that are mainly used for converting alternating currents from one voltage to another while another voltage is introduced to one called or also known as primary.

This magnetizes the iron core. A voltage is then expected to be induced to another coiled which is called the secondary or output coil.

Why Are Voltage Transformers Important?

As you know, transformers are electrical devices that are mainly used for converting alternating currents from one voltage to another while another voltage is introduced to one called or also known as primary.

This magnetizes the iron core.

A voltage is then expected to be induced to another coiled which is called the secondary or output coil.

What are High Voltage Transformers?

high voltage transformers are also voltage transformer converters that are capable of transforming voltages from one level or phase configuration to another.

In a common setting, this typically ranges from higher to lower. Moreover, they are suitable for features for electrical isolation, power distribution, and control.

This also includes instrumentation application.

Basically, this kind of transformer’s design will depend on the principle of magnetic induction between coils to convert voltages and/or current levels.

Furthermore, they can also be tweaked with either a single-phase primary configuration or a three-phase one.

The size and price of a transformer will increase if you move down the listing of primary high power voltage windings.

When it comes to the single-phase primary configurations, this will include single, dual, quad, etc. In terms of a 5-lead configuration, the primary will require more copper than a quad primary. A ladder is the least economical primary configuration.

Three-phase transformers are also connected in delta or wye configurations.

A wye-delta transformer will have its primary winding connected in a wye. With regards to its secondary winding, it will be connected via delta.

Speaking of Delta, a delta-wye transformer is expected to have its primary windings connected in a delta and its secondary windings will be connected in a wye.

Three-phase high voltage power configurations will always have a delta, namely: delta – wye (Y), wye (Y) – wye (Y), wye (Y) – delta, wye (Y), and single-phase and international variants.

Basically, the primary frequencies of an incoming voltage signal to the primaries available for power transformers will include 50 Hz, 60 Hz, and even 400 Hz.

The most common Hz for European power is 50 Hz.

For North American Power, the 60 Hz variant is the most commonly used. But what about the 400 Hz variant? Well, it is mostly used for aerospace applications.

The maximum primary input voltage rating will be another element to consider as well.

Transformers are expected to have more than one primary winding if its application is for several nominal voltages.

Moreover, this helps prevent short circuits.

Another important specification that you should thoroughly look into when purchasing a high voltage transformer is the maximum secondary voltage rating, maximum power rating, maximum secondary current rating, and as well as output type.

A transformer will also provide more than one secondary voltage value, and the rated power of the transformer is the sum or equal of the Volts and Amperes for all of the secondary windings.
For output choices, this will include alternating currents and dc currents.

With regards to the alternating current waveform output, the voltage will depend on the value that is given in R.M.S values.
It is important for you to contact DAELIM for professional consultation so that you will know the waveform options.

For direct current secondary voltage output power supply, speak with the transformer’s manufacturer as well for the type of rectification you prefer.
This can be constructed as either a laminated transformer or a toroidal transformer.

If you do not know what a toroidal transformer is, it is basically a transformer that has copper wires wrapped around a cylindrical core, this is to prevent the magnetic flux from damaging, which will occur within the coil so that it will not leak out.

In terms of the coil efficiency, if it is good, then the magnetic flux will have little to almost no influence on the other components.

Laminated transformers will contain laminated-steel cores as well and they are called E-1 transformers.

The steel laminations are insulated or cooled with a non-conducting material like varnish.

Afterward, they will be formed into a core to reduce electrical losses.

Power transformers have many classifications or types as w well and these include control transformers, current transformers, distribution transformers, instrument transformers, and many more.

About Bin Dong

Hello, I am Bin, General manager of Daelim which is a leading transformer manufacturer. If you have problems when you are looking for the equipment, what you need to do is tell us.

Custom Voltage Transformer

When you need to find more than just existing transformers, Daelim’s Transformer Service Center can help you design and produce distribution transformers that meet your unique needs.

We have our own factory and a professional team of engineers, which can design and modify application requirements that meet all your conditions.

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