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TUDY ON THE IMPACT OF HARMONIC
DISTORTION IN CESC LT SYSTEM
MAINAK GHOSH, MOUSAM DUTTA, ARPAN KUMAR PRAMANICK
LT FAULT MANAGEMENT CENTRE, MAINS
Abstract
The concept of power quality, which had until a few years back, been too insignificant a topic to be considered
seriously from a utility perspective, will become as significant an issue as the reliability of power supply in the
near future. The problems of neutral overloading, equipment overheating and system losses due to harmonic
proliferation will only increase from here on out due to increase in non-linear load drawn by electronic devices,
EV charging stations and distributed solar power generation. This paper gives an extensive overview of a series
of measurements done on CESC LT Distribution system to assess the significance of harmonic impurity prevalent
in the network. It further explores the technical and economical aspects of the pollution injected into the power
system in a widely distributed manner by the 3.3 million LT consumers catered to by CESC and also briefly
investigates about the possible remedial measures to the Harmonic problem.
Keywords: Power quality, Harmonics, system losses, remedial measures
INTRODUCTION ➣ A distorted current/voltage waveform
containing harmonics can be represented by
A harmonic is a signal or wave whose frequency is an a combination of the fundamental waveform
integral (whole-number) multiple of the frequency of and various other sinusoidal waveforms with
some reference signal or wave. different frequencies. This is expressed by the
Fourier series stated below.
➤ Ideally, system voltage and current waveforms are
sinusoidal with presence of linear loads. Harmonics hf
are a distortion of the normal electrical current/
voltage waveform, generally transmitted by ¦y(t) Y0 Yh 2 sin(hwt Mh)
nonlinear loads, where the AC voltage is converted h1
to a DC voltage. The distortion travels back to the
power source and can affect other equipment ➤ Where ω is the fundamental frequency (equal to 50
connected to the same source. Hz) in CESC system.
➤ Current harmonics are caused by the action of non- ➤ Odd harmonics have frequency which are odd
linear loads such as rectifiers, discharge lighting, or integer multiples of the fundamental frequency
saturated electric machines. Voltage harmonics are (h = 3,5,7,9,11,13,…) & even harmonics have
caused by the current harmonics flowing through frequency which are even integer multiples of the
an impedance. Voltage distortion depends on fundamental frequency (h= 2,4,6,8,…)
System impedance and amount of distorted current.
➤ Harmonic number 0 is the constant or
DC component of the waveform. DC component
is the net difference between positive & negative
halves of complete waveform cycle.
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DISTORTION IN CESC LT SYSTEM
MAINAK GHOSH, MOUSAM DUTTA, ARPAN KUMAR PRAMANICK
LT FAULT MANAGEMENT CENTRE, MAINS
Abstract
The concept of power quality, which had until a few years back, been too insignificant a topic to be considered
seriously from a utility perspective, will become as significant an issue as the reliability of power supply in the
near future. The problems of neutral overloading, equipment overheating and system losses due to harmonic
proliferation will only increase from here on out due to increase in non-linear load drawn by electronic devices,
EV charging stations and distributed solar power generation. This paper gives an extensive overview of a series
of measurements done on CESC LT Distribution system to assess the significance of harmonic impurity prevalent
in the network. It further explores the technical and economical aspects of the pollution injected into the power
system in a widely distributed manner by the 3.3 million LT consumers catered to by CESC and also briefly
investigates about the possible remedial measures to the Harmonic problem.
Keywords: Power quality, Harmonics, system losses, remedial measures
INTRODUCTION ➣ A distorted current/voltage waveform
containing harmonics can be represented by
A harmonic is a signal or wave whose frequency is an a combination of the fundamental waveform
integral (whole-number) multiple of the frequency of and various other sinusoidal waveforms with
some reference signal or wave. different frequencies. This is expressed by the
Fourier series stated below.
➤ Ideally, system voltage and current waveforms are
sinusoidal with presence of linear loads. Harmonics hf
are a distortion of the normal electrical current/
voltage waveform, generally transmitted by ¦y(t) Y0 Yh 2 sin(hwt Mh)
nonlinear loads, where the AC voltage is converted h1
to a DC voltage. The distortion travels back to the
power source and can affect other equipment ➤ Where ω is the fundamental frequency (equal to 50
connected to the same source. Hz) in CESC system.
➤ Current harmonics are caused by the action of non- ➤ Odd harmonics have frequency which are odd
linear loads such as rectifiers, discharge lighting, or integer multiples of the fundamental frequency
saturated electric machines. Voltage harmonics are (h = 3,5,7,9,11,13,…) & even harmonics have
caused by the current harmonics flowing through frequency which are even integer multiples of the
an impedance. Voltage distortion depends on fundamental frequency (h= 2,4,6,8,…)
System impedance and amount of distorted current.
➤ Harmonic number 0 is the constant or
DC component of the waveform. DC component
is the net difference between positive & negative
halves of complete waveform cycle.
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