Electrical Isolators Types of Electrical Isolators Types of Electrical Isolators based on location Tap Changer

1. Tap Changer
Why tap changer always connected to HV side
Urooj Abid (syedauroojabid@gmail.com)
NED University Of Engineering & Technology
K-Electric Internship

3. The isolator is one type of switching device, and the main
function of this is to make sure that a circuit is totally not
triggered in order to perform the preservation. These are
also recognizable like isolation switches to isolate the
circuits. These switches are applicable in industrial,
distribution of electrical power, etc. It is one type of
mechanical switch used to isolate a fraction of the electrical
circuit when it is required. Isolator switches are used for
opening an electrical circuit in the no-load condition. It is
not proposed to be opened while current flows through the
line. Generally, these are employed on circuit breaker both
the ends thus the circuit breaker repair can be done easily
without any risk.

5. This type of isolator consists of three loads of post insulators. The middle insulator holds a
flat male or tubular contact that can be turned straightly by a spin of middle post insulator.
The rotation of the middle post insulator can be done by a lever method at the bottom of the
post insulator, as well as it is related to manual operation (operating handle) or motorized
operation motor (using motor) of the isolator via a mechanical knot rod. The horizontal
double break disconnect or is suitable for substations with limited phase space and
installation with low vertical clearance.

6. In this type of isolator, the arm contact is separated into two elements. The first arm contact
holds male contact, as well as second arm contact, holds female contact. The arm contact
shifts because of the post insulator rotation upon which the arm contacts are fixed. The post
insulators rotation stacks in reverse to each other which makes to shut the isolator by
shutting the arm contact. Post insulators counter rotation stacks to open the arm contact, as
well as an isolator, rotate into an off condition. Generally, the motor operated isolator is used
however an emergency manual operated isolator is also offered.

7. The pantograph type isolator permits current switchgear installation, and it requires the least
space. This type of insulator includes a post insulator as well as an operating insulator.

8. BUS SIDE ISOLATOR LINE SIDE ISOLATOR
Bus side type of
Isolator are the
isolators that
connects by the
major bus.
Line side type of
Isolator are the
isolators that
connects by the
major bus.
TRANSFER SIDE ISOLATOR
Transfer bus side
isolators are the
that stay
connected by the
major bus of a
transformer

10. A tap changer is an apparatus for changing the connection to an
electrical transformer from one tap to another, so as to vary the turns
ratio and hence control the output voltage under a varying load.
The purpose of a tap changer is to regulate the output voltage of a
transformer. It does this by altering the number of turns in one winding
and thereby changing the turns ratio of the transformer. There are two
types of transformer tap changers: an on-load tap changer (OLTC) and a
de-energized tap changer (DETC).

11. The HV winding generally wound over LV winding hence it is easier to
access the HV winding turns instead of LV winding and Because of high
voltage the current through the HV winding is less compared to LV
windings, hence there is less “wear” on the tap changer contacts. Due
this low current, in on load tap changer the change over spark will be
less.