Current transformers (CTs) are an essential component in the electrical power industry providing a means of measuring and monitoring the flow of electrical current in power transmission and distribution systems. These devices are used in a wide range of applications, from residential and commercial buildings to large industrial facilities and offer several advantages over traditional methods of measuring current. In this article, we will explore the advantages of current transformers and how they can improve the efficiency and safety of your electrical systems.
Advantages of Current Transformers
Current transformers have many benefits for the electrical circuit such as:
1. Measures high currents
The basic function of a current transformer is to convert primary current into a proportional secondary current that may be monitored or utilized to regulate different circuits. The bigger current values are simple to measure.
Current transformers can be used in a synthetic circuit to measure the fault current, facilitating the safe measurement of large currents, often in the presence of high voltages. The primary winding is connected in series with the source current to be measured, while the secondary winding is normally connected to a meter, relay or a burden resistor to develop a low-level voltage that is amplified for control purposes.
2. High-effective cores
Commonly, cores with high effective permeability are used in current transformers to minimize magnetizing current and reduce errors. The core’s permeability is a measure of how easily magnetic flux can pass through it, and cores with high effective permeability can help minimize the magnetizing current and reduce errors in the CT’s operation.
3. High electrical isolation
Its capability to isolate the high voltage and current to low values ensure safe operations and safe handling of the equipment. Current transformers offer electrical isolation among measuring instruments & high-voltage power circuits. So that electrical insulation requirements can be reduced in protective circuits & measuring instruments.
4. Simple construction
Current transformers are widely used as measurement or protective transformers. Another advantage of the current transformer is its simple construction and ease of installation.
5. Easy supply and control functions
A current transformer is powered by the current it measures. It does not require additional power. Besides, the output signal of a CT can directly trigger the electromechanical relays. It does not require additional amplification.
6. Effective measurements
Numerous instruments can be fed with a single transformer. Besides, the measurement results are not affected by the temperature of windings or magnetic cores, if within acceptable limits.
7. Clamp-on types
The placement of the current transformer sets limits for the shape and size. The current transformer is placed inside the induction motor’s terminal box, around the phase conductor. This limits the maximum size of the transformer core. Clamp-on cores can be used to ease the installation so that the transformer can be installed without disconnecting the phase conductor from the motor end.
8. Easy maintenance and installation
Damaged parts of a CT can be easily replaced. Current transformers have robust mechanical strength and a compact design. They are easy to transport, store and install. Besides, they are maintenance-free throughout their lifespan.
With the standardization of current transformer secondary winding ratings, it is possible to standardize instruments around these ratings and, therefore, there is a great reduction in the costs of current transformers and instruments.
10. Safe AC measurement
Current transformers do not allow the measurement of DC signals, so they cannot be suitable for dielectric discharge detection; however, they can be used in the measurements of inductive currents and voltage waveforms with secondary load impedance. External magnetic fields barely affect the measurement results.
11. Various types
Current transformers have various types such as molded case, summation, cable split-core, three-phase, DIN rail, compact, flexible, split-core residual and differential current transformer. All these types have different functions.
12. Wide applications
CTs can be used in wide applications such as branch circuit power monitoring, substation error detection, the current measurement for motor protection, industrial electricity metering and smart electricity metering.
In conclusion, current transformers are essential components in the electrical power industry that provide numerous benefits for measuring and monitoring the flow of electrical current in power transmission and distribution systems. The advantages of current transformers include measuring high currents, high-effective cores, high electrical isolation, simple construction, easy supply and control functions, effective measurements, clamp-on types, easy maintenance and installation, cost-effectiveness, safe AC measurement, various types, and wide applications. The use of current transformers improves the efficiency and safety of electrical systems and ensures that equipment is operated safely. With their versatility and effectiveness, current transformers are a vital part of modern electrical systems.