DIRECT VOLTAGE MODULE

1
DIRECT VOLTAGE MODULE
Project Members Dr. Stan Grzybowski E-mail
stangrzy_at_ece.msstate.edu Phone (662)
325-3842 Trinity Baggett E-mail
tab1_at_ece.msstate.edu Phone (662)
324-5083 William Zender E-mail
wlz1_at_ece.msstate.edu Phone [phone]

2
TEAM MEMBERS

Pictured from left to right Team Member
William Zender Faculty Advisor
Dr. Stan Grzybowski Team
Leader Trinity Baggett
3
ABSTRACT
The Direct Voltage Module, also known as a DC
module is used for high voltage testing. The
main application of a DC Module is to determine
the positive and negative flash over on high
voltage components. This type of testing is
necessary because DC voltage has different
effects compared to AC. This type of equipment
is important to high voltage laboratories such
as the High Voltage Laboratory found here at
Mississippi State University.
4
MOTIVATION

• MISSISSIPPI STATE UNIVERSITYS HIGH VOLTAGE
  LABORATORY REQUIRES AT LEAST 525 KVDC FOR TESTING
  HIGH VOLTAGE EQUIPMENT
• OUR SPECIAL INTEREST IN POWER AND HIGH VOLTAGE
  LED US TO PRODUCE THIS DIRECT VOLTAGE MODULE.

5
REQUIREMENTS

• RIPPLE FACTOR lt 5
• CURRENT LIMITATION lt 2.0 Amps
• CASCADING
• BLEED-OFF RESISTOR
• INSULATING COMPOUND

6
RIPPLE
7
BASIC LAYOUT OF CIRCUITRY
TO MORE DETAILED SUB-CIRCUITS
8
CURRENT LIMITATION
9
CASCADING
TRANSFORMER CONFIGURATION BLOCK DIAGRAM
10
BLEED-OFF RESISTORWHY HAVE A BLEED-OFF RESISTOR?
For safety reasons, the bleed-off resistor will
slowly dissipate the capacitors.
11
INSULATING COMPOUND

• OIL INSULATION
• ADVANTAGES
• EASILY ACQUIRED
• BETTER HEAT TRANSFER
• DISADVANTAGES
• ADDED WEIGHT
• AGEING PROCESS REDUCES INSULATION STRENGTH
• SLUDGE BUILD UP REDUCES CIRCULATION OF OIL
• ENVIROMENTAL IMPACT

• SF6 GAS INSULATION
• ADVANTAGES
• VERY LARGE DIELECTRIC STRENGTH
• THERMAL STABILITY
• LIGHT WEIGHT
• EASILY ACQUIRED
• LOW TEMPERATURE CONDENSATION

• DISADVANTAGES
• PERFORM VACCUM TO PRESSURIZE GAS

12
CIRCUIT SCHEMATIC
13
VARIOUS DESIGN CALCULATIONS
R1, R2 Calculations R1, R2 640 M, which are
actually five 250 M ohm resistors in series Vc
(t) Vmax e - (t/R1, 2C) i Vmax e -
(t/R1, 2C)/ 640 M .156 mA P I2 R1, 2
.156 mA2 20 M .488 W (1 watt resistors were
used)
14
VARIOUS DESIGN CALCULATIONS
R3, R4 Calculations MAX I FOR TRANSFORMER
WINDINGS 17 mA R3, R4 60 K ohm, which are
actually ten 6 K ohm resistors in
series Capacitor current when shorted I
175K/120K 1.46 A (maximum capacitor current 2
A) Power R3, 4 I2 R3, 4 Power R3, 4
.0172 6K 1.73 W (2 watt resistors were
used)
15
VARIOUS DESIGN CALCULATIONS
R5, Calculations R5 1250 Mega-ohms set for
output measurement I (r5) 175 KV / 1250
Mega-ohm .14 mA P .14mA2 250 Mega-ohm
4.9 W Five 250 mega-ohm resistors rated at 6
watts were used.
16
SIMULATION
17
TEST RESULTS
18
TEST RESULTS
19
TEST RESULTS
RIPPLE AMPLITUDE .5(VMAX-VMIN)
.5(230- (-230)) 230
MILLIVOLTS RIPPLE FACTOR RIPPLE
AMPLITUDE/VMEAN
.32 CURRENT _at_ 175 KVDC IS 1.5 mA. CAPACITOR
VALUE 5.7 nF RIPPLE AMPLITUDE (I T)/(2C)
RIPPLE FACTOR 1.27
20
REFERENCES
E. Kuffel, W. S. Zaengl High Voltage
Engineering Fundamentals, Pergamon Press Inc.,
Elmsford, New York 1984. J. D. Craggs, J. M.
Meek, High Voltage Laboratory Techniques,
Butterworths Scientific Publications, London
(1964). J. Schwab, High Voltage Measurement
Technique, M.I.T. Press, Cambridge,
Massachusetts(1972). G. W. Bowlder,
Measurement in High Voltage Test Circuits,
Pergamon Press, Oxford(1975). D. Kind, An
Introduction to High Voltage Experimental
Techniques, Friedr Vieweg Sohn
Verlagsgeselchaft mbh, West Germany(1978). M.
Khalifa, High-Voltage Engineering, Theory and
Practice, Marcel Dekker, New York, New
York(1990). M. S. Naidu, V. Kamaraju, High
Voltage Engineering, Second Edition,
McGraw-Hill, New York(1995). T. J. Gallagher,
A. J. Pearmain, High Voltage Measurement,
Testing and Design, John Wiley Sons, New
York(1983). K. Denno, High Voltage Engineering
in Power Systems, CRC Press., Boca Raton,
Florida(1992)
21
FUTURE IMPROVEMENTS

• CONTROLS ALLOWING THE OUTPUT VOLTAGE TO BE
  VARIED VIA REMOTE CONTROL
• DESIGNING AND CONSTRUCTING A DIRECT
  VOLTAGE MODULE THAT IS EXTREMELY SMALL
• DESIGNING A DIRECT VOLTAGE MODULE CAPABLE OF
  PRODUCING 525KVDC