Transformers are widely used devices in electrical and electronic domain. The role that transformer plays in our power system is a very crucial one as it enables economical, safe and reliable generation and distribution of electricity with appropriate voltage levels. Just like everywhere, use of transformers in Nepal is also popular as they play a crucial role in our power system and help in offering the people a reliable and secure power.
Transformers are also categorized into several types depending on the different types of applications they are used in. However, the fact to note is that all different types of transformers work on or follow the same principles but they may vary in the way they are built. Transformers are characterized into several types according to several factors such as voltage level, on basis of core material used, on basis of winding arrangement and on the basis of usage or domain (power or electronics). Usually, people in Nepal lack these knowledge and is also a big factor behind why so much problems arise when dealing with transformers in Nepal. All these different types of transformers may be needed to operate and maintained in different manner than the other to be kept in top condition. In many cases, when people work on transformers without these appropriate knowledge on what type of transformer they are working on, they might put themselves in danger as well as risk the machine.
When talking in brief about the power domain, this field in concerned with the power generation, distribution and measurement. These transformers are generally used outdoors but can also be used for indoor purposes if required. Differentiating transformers according to the power usage is very important as by doing so, we can accommodate safe and successful power delivery to the substations and end users. According to power usage, transformers can be differentiated into two types: Distribution transformer and Power transformer. If we can get proper knowledge about the transformers on basis of power use, we can operate on them accordingly and protect a lot of transformers in Nepal from being damaged unnecessarily.
Distribution Transformer
A distribution transformer transforms the voltage to end lines or end users, thus the electricity it transfers is ready for immediate use. Distribution transformers are step down transformers and they convert high grid voltage to user required voltage. Distribution transformers are comparatively smaller or bigger in size, and its size depends on conversion capacity and ratings. Generally they have an electric rating of less than 200 kVA. These transformers can also be of single phase or three phase which means that when the transformer is operating, they are surrounded by windings through which current will flow. The most common core configuration for both energy and distribution is with “E” core kernels and this type is considered classical and conventional. Distribution transformers also have a different type of classification based on location it is used. These type of transformers can be mounted or placed at several locations, such as a utility pole, underground chambers concrete pad or even enclosed inside a steel box, adding to its advantage and effectiveness. Distribution transformers have to be designed in a different manner as all day long use and efficiency needs to be considered while designing it.
Power Transformer
Power transformers acts as a bridge between power generator and the primary distribution grid. Power transformers are built in larger sizes compared to distribution transformers as they are used to transfer energy to public electricity supply. The ratings in power transformers can vary and has lot more potential than other types of transformers. The power ratings can be from 30 KVA to 700 KVA or in some high demand cases, it can be even more than 7000 KVA. Due to high power transmissions needed, construction of power transformers is also very critical. Constructing these machines include durable insulating peripherals, a well-balanced cooling system and are filled with oil. Power transformers mostly follow the step up principle and convert low voltage high current to high voltage low current. They play an important role in our power system as they help in minimizing power loss in the distribution systems. These type of complex transformers work in three phases, but in some cases, single phase transformers are also used. The three phase transformers are also most costly than single phase transformers. Power transformers are generally bigger is sizes and can contain a lot of energy than distribution transformers. Hence they are placed inside power plants and other captivated areas preventing general public from getting in contact.
Difference between power and distribution transformers
Definition
Power transformers are electrical devices that step-ups the voltage, without changing the frequency and ensure efficient transmission of electricity. On the other hand, distribution transformers steps down voltage where electricity is ready to be used by the end users.
Size
Power transformers are larger in size and have a more complex installation while distribution transformers come in smaller sizes and can be fit and installed more flexibility.
Winding connection
Primary windings of a power transformer are connected in a star and secondary windings to delta connections. However, in distribution transformers the primary windings are bound in delta and secondary in star type.
Specifications
Power transformers work on higher voltages and commonly are rated above 200 MVA. On the other hand, distribution transformers work on lower to middle voltage ranges and commonly rated below 200 MVA.
Losses
Losses of energy while using power transformers are more constant and optimal losses occur at full load operations. In case of Distribution transformers, fluctuations and optimal losses when operating around 75% of full load.
Efficiency
Efficiency of power transformers is also greater and they can work offering maximum efficiency. On the other hand, distribution transformers offer around 60% - 70% efficiency as the load fluctuates.
So, basically, electric transformers is an energy converter and these transformers are further divided into distribution and power transformers on the basis of voltage that need to be converted. Here at BN Mahto, we provide the best distribution transformers in Nepal and we always offer best quality products and services and have been successfully lighting the nation since 1987.