ABSTRACT:
Until
recently, most of the power system equipment in industrial grids has been
operating with deviations from the nominal voltage and frequency supplied by
the utility. However, power electronics based equipment is vulnerable to such
deviations and might get damaged in case of possible grid faults. This paper
addresses this issue by proposing a stabilizing device that can be connected
between the public grid and the industrial grid which provides not only power quality
and security of supply during fault for the industrial grid but also ensuring
the power quality for the public grid.
KEYWORDS:
1.
Public grid
2.
Industrial grid
3.
Power quality
4.
Security of supply
5.
Grid stability
SOFTWARE:MATLAB/SIMULINK
Fig.
1. Device representation
Fig.
2. Harmonic current injection and compensation
Fig.
3. Individual harmonic distortion voltage for different Sk
’’
Fig.
4. THDu for different Sk’’
Fig.
5. Voltage behavior during load switching with and without Netz-Patron unit
Fig.
6. Voltage behavior during motor starting with and without Netz-Patron unit
Fig.
7. Voltage behavior during three phase fault with and without Netz-Patron unit
CONCLUSION:
The paper presents the
different functionalities of the Netz-Patron unit that is designed to provide different
support functionalities like harmonic compensation and voltage support in case
of disturbed grid operation. In order to analyze the effectiveness of the
Netz-Patron unit, a simulation model has been developed within the DIgSILENT PowerFactory
software environment. The different scenarios and their simulation results are
shown in this paper and the behavior of different functionalities has been
analyzed. A brief summary of the main findings is given in the following. A 900
kVA active filter has been considered to provide harmonic compensation from the
AC/DC converter for Sk ’’ greater than 50 MVA.
In this paper, the
study has been carried out by considering a class 2 type of load with injected harmonics
of 10 minutes average value (long term). The harmonic values considered for the
study are not measured values, but typical values observed in practice. Real
laboratory tests are planned to be performed to check the harmonics injected by
th
load before designing the Netz-Patron
unit to provide harmonic compensation. The effectiveness of the voltage support
function provided by the Netz-Patron unit in case of any disturbance registered
at the PCC has also been analyzed in this paper.
Future work is planned
to focus on a multimaster concept
which implies the analysis of the parallel operation of several Netz-Patron
units connected at the PCC of different industrial grids or same industrial
grid in the medium voltage network.
REFERENCES:
[1] EPRI PEAC Corporation, "C. E.
Commission:, Power Quality Solutions for Industrial Customers," August
2000.
[2] R.C.Dugan, M.F.McGranaghan,
S.Santoso and H.W.Beaty, Electrical Power Systems Quality, second edition,
McGraw- Hill, 2004.
[3] W. Reid, "Power Quality Issues
- Standards and Guidelines," in IEEE Transactions of Industry Applications
Vol.32,No.3, 1996.
[4] DIN EN 61000-2-4: Electromagnetic
compatibility (EMC) Part 2-4: Environment – Compatibility levels in industrial plants
for low-frequency conducted disturbances, VDEVerlag GmbH, 2002-06.
[5] DIN EN 61000-4-11: Electromagnetic
compatibility (EMC) Part 4-11: Environment – Testing and measurement techniques
– Voltage dips, short interruptions and voltage variations immunity tests for
equipment with input current less than 16 A per phase, February 2005.
