PowerApps software product is a Proprietary Property of Dr.Raghunatha Ramaswamy. No company with whom Dr.Raghunatha Ramaswamy was associated in the past either as consultant or as an employee do not own the proprietary property for this software.
Harmonics in power systems can result in undesirable influence such as Capacitor
heating/failure, Telephone interference, Rotating equipment heating, Relay misoperation,
Transformer heating, Switchgear failure, Fuse blowing. The main sources of harmonics
in power system are static power converters, arc furnaces, discharge lighting and
any other load that requires nonsinusoidal current. In order to limit the harmonic
current propagation in to the network, harmonic filters are placed close to the
source of the harmonic currents. Harmonic filters provide low impedance paths to
harmonic currents and thus prevent them from flowing into the power network. Harmonic
analysis program computes indices such as total voltage harmonic distortion factor
at system buses to evaluate the effect of the harmonic sources and to evaluate the
effectiveness of the harmonic filters. Also, driving point impedance plots of the
buses of interest are generated to identify whether series or parallel resonance
phenomenon occurs at any harmonic frequency of interest.
We use 4 step approach as described in this section.

In the
first step for existing and functional networks harmonic current measurements is
performed at selected points to identify the harmonic currents injected into the
network by the harmonic sources. These measurements reflect harmonic currents
for one operating configuration and the loads prevailing at the time of
measurements only. These may not represent conservative estimates of harmonic
currents available.

In the
second step, the measurement information of the first step will be used along
with design data of harmonics where available from nonlinear loads, generating
harmonic currents. A computer network model will be prepared as per IEEE
standards and the effect of various harmonic sources at various harmonic orders
will be examined. Various harmonic distortion factors will be computed as
outlined in relevant IEEE standards. The advantage of computer model and
simulation is that it can take care of large number of operating configurations
and conservative estimates of harmonic currents, which cannot be covered by
field measurements. Field measurements of the first step, can however be used to
validate the computer model developed.

In the
third step, harmonic driving point impedances of all buses of interest will be
generated at various harmonic orders and plots of the driving point impedances
will be generated with respect to a range of harmonic orders [orders 1 through
50]. These plots indicate series and parallel resonance conditions in network.

In the
fourth step, analysis of results of the first 3 steps will be carried out and
solutions needed to solve any harmonic related problems will be obtained. These
solutions are verified by using the computer model developed. The problems that
might arise could be excessive harmonic distortion factors beyond relevant IEEE
specified standards, existence of resonance conditions close to an exciting
harmonic frequency. Where these problems are encountered, solutions will be
provided by introduction of harmonic filters and its design will be verified
again by using the computer model developed. Recommendations include
specifications on sizing of individual components of the harmonic filters.
 Case 1: In this case the power supply to individual loads are supplied by
dedicated panels, with no other loads other than the specific nonlinear load.
The load size is significantly large enough to warrant a specic dedicated
harmonic filter. The measurements will be taken for this load feeder
 Case 2: A single supply switch board supplies several nonlinear loads. All
loads are sufficiently small and nearly similar to each other. In this case
dedicated harmonic filters for individual loads may not be necessary. A common
filter may be provided at the incomer, provided the outgoing feeder loads are
reasonably constant. The measurement will be done on the incomer of the switch
board only.
 Case 3: A single switch board supplies several nonlinear loads. The nature of
the loads are significantly different from each other. The net switch board load
is not constant or uniform making it difficult to arrive at a common filter at
the incomer. In this case we take harmonic measurements at each outgoing feeder
and design individual load filters.
Apart
from the above cases for harmonic measurements for purpose of filter design, it
may be necessary to carryout measurements at point of common power coupling at
HV levels to ensure that statutory requirements are satisfied.
From the guidelines provided, it is fairly straightforward to examine the
electrical network and to determine the number of measurement points.
Measurements may have to be performed at different short circuit levels at the
point of grid coupling as the electrical network characteristics changes with
fault levels.

Distortion Factor Calculations as per IEEE 519 Standard.

Impedance Frequency Scans to identify parallel and series resonance points and bus
locations.

Modelling of harmonic sources and filters.

Modelling of all electric circuits as function of frequency.

Analysis using design data or Field measurements.

Analysis for various network configurations, fault levels.

Simultaneous solution of multiple islanded network.

Single execution and report generation for multiple study cases.

Calculation of harmonic current flows in specified circuit elements.

Display of computed harmonic distortion factors, harmonic bus voltages, harmonic
currents on single line diagram for all study cases.

Evaluation of adequacy of filter design.

Design of filters considering the harmonic currents to be filtered and reactive
power compensation needed at fundamental frequency.

Field measurements of power flows, harmonics and reports on the same.
ValidationDocument_HarmonicAnalysis_IEEEStd399_1997
Typical Harmonic and Power Quality Measurements Report Extract