Bundled Conductors are used in transmission lines where the voltage exceeds 230 kV. At such high voltages, ordinary conductors will result in excessive corona and noise which may affect communication lines.  The increased corona will result in significant power loss.  Bundle conductors consist of three or four conductors for each phase. The conductors are separated from each other by means of spacers at regular intervals.  Thus, they do not touch each other.

1. Bundle conductors in
transmission line
By: Chandna kumar

2. What is Transmission Line

3. Transmission Line cont.……
• Electric-power transmission is the bulk transfer of electrical
energy, from generating power plants to electrical substations
located near demand centers.
• Historically, transmission and distribution lines were owned by the
same company, but starting in the 1990s, many countries have
liberalized the regulation of the electricity market in ways that
have led to the separation of the electricity transmission business
from the distribution business.
• Transmission lines, when interconnected with each other,
become transmission networks. The combined transmission and
distribution network is known as the "power grid"

5. Problem In Transmission Line
• Electricity is transmitted at high voltages (120 kV or above) to
reduce the energy losses in long-distance transmission.
• One of the key concerns in the transmission of electricity is the
power loss in transmission lines, dissipated as heat due to the
resistance of the conductors.
•
High-voltage transmission lines are used to transmit electric
power over long distances. Normally, high voltage (HV)
transmission power lines are made of high voltage (between 138
and 765 kilovolts) conducting lines of copper and/or aluminum.

6. Bundle Conductors
• Bundled Conductors are used in transmission lines
where the voltage exceeds 230 kV.
• At such high voltages, ordinary conductors will
result in excessive corona and noise which may
affect communication lines.
• The increased corona will result in significant
power loss. Bundle conductors consist of three or
four conductors for each phase.
• The conductors are separated from each other
by means of spacers at regular intervals. Thus,
they do not touch each other.

7. How Bundle Conductor Work.
for extra high voltage lines corona causes a large problem if the
conductor has only one conductor per phase. Corona occurs
when the surface potential gradient of a conductor exceeds the
dielectric strength of the surrounding air.
This causes ionization of the area near the conductor. Corona
produces power loss. It also causes interference with
communication channels. Corona manifests itself with a hissing
sound and ozone discharge. Since most long distance power lines
in India are either 220 kV or 400 kV, avoidance of the occurrence
of corona is desirable.

8. • The high voltage surface gradient is reduced considerably by
having two or more conductors per phase in close proximity. This
is called conductor bundling .
• The conductors are bundled in groups of two, three or four . The
conductors of a bundle are separated at regular intervals with
spacer dampers that prevent clashing of the conductors and
prevent them from swaying in the wind. They also connect the
conductors in parallel.

10. Advantage Of Bundle Conductor
• Bundled conductors are primarily employed to reduce the corona loss and
radio interference. However they have several advantages:
• Bundled conductors per phase reduces the voltage gradient in the vicinity of
the line. Thus reduces the possibility of the corona discharge. (Corona effect will
be observed when the air medium present between the phases charged up
and start to ionize and acts as a conducting medium. This is avoided by
employing bundled conductors)
• Improvement in the transmission efficiency as loss due to corona effect is
countered.

11. Advantage Cont..
• Bundled conductor lines will have higher capacitance to neutral
in comparison with single lines. Thus they will
have higher charging currents which helps in improving the
power factor.
• Bundled conductor lines will have higher capacitance and lower
inductance than ordinary lines they will have higher Surge
Impedance Loading (Z=(L/C)1/2). Higher Surge Impedance
Loading (SIL) will have higher maximum power transfer ability.
• With increase in self GMD or GMR inductance per phase will be
reduced compared to single conductor line. This results in lesser
reactance per phase compared to ordinary single line. Hence
lesser loss due to reactance drop.