Potential transformer

Potential transformer is a voltage step-down transformer that reduces the voltage of a high voltage circuit to a lower level for the purpose of measurement. These are connected across or parallel to the line which is to be monitored.


The basic principle of operation and construction of this transformer is similar to the standard power transformer. In common, the potential transformers are abbreviated as PT.

The primary winding consists of a large number of turns which is connected across the high voltage side or the line in which measurements have to be taken or to be protected. The secondary winding has a lesser number of turns that are connected to the voltmeters, or potential coils of wattmeter and energy meters, relays, and other control devices. These can be single-phase or three-phase potential transformers. Irrespective of the primary voltage rating, these are designed to have the secondary output voltage of 110 V.

Since the voltmeters and potential coils of other meters have high impedance, a small current flows through the secondary of PT. Therefore, PT behaves as an ordinary two winding transformer operating on no load. Due to this low load (or burden) on the PT, the VA ratings of PTs are low and in the range of 50 to 200 VA. Compared to the conventional transformer, potential transformers or PTs use larger conductor sizes and core. PTs designed for ensuring greater accuracy and hence, at the time of designing economy of the material is not considered as the main aspect.

Comments

Post a Comment

Popular posts from this blog

wide area network

Image
  A wide area network (also known as WAN), is a large network of information that is not tied to a single location. WANs can facilitate communication, the sharing of information, and much more between devices from around the world through a WAN provider. WANs can be vital for international businesses, but they are also essential for everyday use, as the internet is considered the largest WAN in the world. Keep reading for more information on WANs, their use, how they differ from other networks and their overall purpose for businesses and people, alike. As described above, wide area networks are a form of telecommunication networks that can connect devices from multiple locations and across the globe. WANs are the largest and most expansive forms of computer networks available to date. These networks are often established by service providers that then lease their WAN to businesses, schools, governments, or the public. These customers can use the network to relay and store data or
Read more

Virtual Local Area Network

Image
  Virtual Local Area Network or Virtual LANs (VLANs) are a logical group of computers that appear to be on the same LAN irrespective of the configuration of the underlying physical network. Network administrators partition the networks to match the functional requirements of the VLANs so that each VLAN comprises a subset of ports on a single or multiple switches or bridges. This allows computers and devices in a VLAN to communicate in the simulated environment as if it is a separate LAN. VLAN  is a custom network that is created from one or more local area networks. It enables a group of devices available in multiple networks to be combined into one logical network. The result becomes a virtual LAN is administered like a physical LAN. The full form of VLAN is defined as Virtual Local Area Network. The below topology depicts a network having all hosts inside the same virtual LAN. Without VLANs, a broadcast sent from a host can easily reach all network devices. Each and every device
Read more

Junction Field Effect Transistor

Image
The Junction Field Effect Transistor , or JFET is a voltage controlled three-terminal unipolar semiconductor device available in N-channel and P-channel configurations In the  Bipolar Junction Transistor   tutorials, we saw that the output Collector the current of the transistor is proportional to input current flowing into The base terminal of the device, thereby making the bipolar transistor a “CURRENT” operated device (Beta model) as a smaller current can be used to switch a larger load current. The  Field Effect Transistor , or simply  FET   however, uses the voltage that is applied to their input terminal, called the  Gate  to control the current flowing through them resulting in the output current being proportional to the input voltage. As their operation relies on an electric field (hence the name field effect) generated by the input  Gate  voltage, this then makes the  Field Effect Transistor  a “VOLTAGE” operated device. The  Field Effect Transistor   is a three-termin
Read more