Thesis (MScEng)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Recent research has shown that standard substation capacitive voltage transformers
(CVTs) and current transformers (CTs) can be used for the measurement of wideband high
voltage phenomena by employing these apparatus in a transconductance topology. With
this topology the voltage waveform can be obtained by integration of the ground return
current in the earth straps of the CVT and the CT. This technique does, however, impose
unique requirements on the amplification and integration instrumentation due to large
dynamic range requirements and the strict offset specifications required for accurate
integration.
This thesis describes a programmable, wideband signal conditioning system for high
voltage (HV) measurements using the transconductance topology. A suitable system
topology, optimised to reduce the problems usually associated with grounding and
electromagnetic interference (EMI) in HV environments, is proposed. This system
consists of an analog signal conditioning subsystem, a digital signal conditioning
subsystem and a high speed serial fibre-optic link.
The analog signal conditioning subsystem conditions the signals from a sensor to levels
suitable for the digitiser of the digital signal conditioning subsystem. The high bandwidth
specification of the application made it necessary to consider both discrete and integrated
implementation of the analog signal conditioning subsystem. Based on the simulated and
laboratory test results of both implementations, the optimum design was chosen for the
developed system. The digital signal conditioning subsystem, which performs the
integration, as well as the serial optic-fibre link control logic was implemented using
programmable logic array (PLA) technology. The digital data is transmitted across the
fibre-optic link. This data is then converted back to an analog signal.
Keywords: High voltage measurements, Transconductance topology. / AFRIKAANSE OPSOMMING: Onlangse navorsing het aangetoon dat standaard substasie kapasitiewe
spanningstransformators en stroomtransformators gebruik kan word om wyeband
hoogspanningsverskynsels te meet deur hierdie apparatuur in 'n transkonduktansie
topologie aan te wend. Met hierdie topologie kan die spanningsgolfvorm verkry word
deur die integrasie van die aardstrome in die aardverbindings van die kapasitiewe
spanningstransformators en stroomtransformators. Hierdie tegniek stel egter unieke
vereistes vir die versterkings- en integrasieinstrumentasie te wyte aan groot dinamiese
bereik vereistes en die streng afset spesifikasies wat benodig word vir akkurate integrasie.
Hierdie tesis beskryf 'n programmeerbare, wyeband seinkondisioneringstelsel vir hoogspanningsmetings
deur van die transkonduktansie topologie gebruik te maak. 'n Geskikte
stelseltopologie, wat geoptimiseer is om probleme, wat gewoonlik met aarding en
elektromagnetiese interferensie in hoogspanningsomgewings geassosieer word, te
verminder, is voorgestel. Die stelsel bestaan uit 'n analoog seinkondisioneringsubstelsel,
'n digitale seinkondisioneringsubstelsel en 'n hoëspoed seriële optiese vesel koppelvlak.
Die analoog seinkondisioneringsubstelsel kondisioneer die seine vanaf 'n sensor na
geskikte vlakke vir die versyferaar van die digitale seinkondisioneringsubstelsel. Die hoë
bandwydte spesifikasie van die toepassing vereis die inagneming van beide diskrete en
geïntegreerde implementerings van die analoog seinkondisioneringsubstelsel. Gebaseer
op gesimuleerde en laboratorium toetsresultate van beide implementerings is die optimale
ontwerp vir die ontwikkelde stelsel gekies. Die digitale seinkondisioneringsubstelsel wat
die integrasie uitvoer, asook die seriële optiese vesel koppelvlak beheerlogika is
geïmplementeer met behulp van programmeerbare logika skikking tegnologie. Die
digitale data word gestuur oor die optiese vesel koppelvlak. Hierdie data word dan terug
geskakel na 'n analoog sein.
Sleutelwoorde: Hoogspanningsmetings, Transkonduktansie topologie.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/51633 |
| Date | 03 1900 |
| Creators | Agjee, F. M. D. E. (Faatima, Moosa, Dawood, Ebrahim) |
| Contributors | Vermeulen, H. J., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 201 p. : ill. |
| Rights | Stellenbosch University |
Page generated in 0.0182 seconds