Thesis (MEng)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: The deployment of Unmanned Aerial Vehicles (UAV) for power line inspection
requires the definition of safe-fly zones. Transient Over-Voltages (TOVs) on the
Overhead Transmission Lines (OHTLs) put the UAV at risk if it encroaches on these
zones.
In order to determine the safe-fly zones of a UAV in the vicinity of OHTLs, realistic
full-scale experimental tests are done. Non-linearity in breakdown effects renders
small-scale testing and computational work inaccurate. Experimental work is used
to describe the close-up approach distances for worst-case scenarios. Testing
cannot provide a full solution due to the limitation of the equipment available.
Further tests must therefore be done at a specialised facility.
Experiments are run in two phases, namely non-linear and linear tests in the High
Voltage (HV) laboratory. The non-linear tests are done to derive Minimum Approach
Distances (MAD). The linear experiments are used to calibrate FEKO, the
simulation tool, to the measurement environment. Once correlation between the
linear test data and the simulated data is found, confidence is derived in both the
simulation model and the test setup. The simulations can then be used to
determine a geometric factor as an input into F. Rizk’s prediction equations.
The Rizk equations are used to describe the safe-fly zones alongside OHTLs as an
addition to the non-linear experimental work. Along with the standard’s
suggestions, the Rizk predictions are formulated in such a way that line-specific
solutions can be determined. The suggested clearance values are provided in terms
of per unit values, which can be selected in accordance with historical line data.
Power line sparking is investigated to better understand the line radiation
phenomenon. This understanding could assist in the line inspection process, as
well as in the layout of power lines near radio quiet areas. Knowledge of OHTL
radiation patterns can aid in the location of corona and sparking sources in the
inspection process. Aerial sparking measurements are taken using a UAV carrying a spectrum
analyser. Measured sparking levels are used to verify a Computational
Electromagnetic (CEM) model. The CEM model can then be used to further
investigate OHTL radiation characteristics. / AFRIKAANSE OPSOMMING: Die aanwending van Onbemande Vliegtuie (UAVs) vir kraglyn inspeksies, vereis die
definiëring van veilige vlieg sones. Oorspannings (TOVs) op oorhoofse kraglyne
(OHTLs) kan hierdie vliegtuie in gevaar stel as hulle die grense van hierdie sones
oorskry.
Om die veilige vlieg sones van 'n UAV in die omgewing van OHTLs te bepaal, is
realistiese volskaalse toetse gedoen. Die nie-lineariteit in afbreek effekte lewer
onakkurate kleinskaal toetse en rekenaar werk. Eksperimentele werk word gebruik
om die benaderde afstande vir die ergste geval te beskryf. Hierdie werk kan nie 'n
volledige oplossing gee nie as gevolg van ‘n beperking op huidige toerusting. Dit
beteken dat verdere toetse, by ‘n meer gespesialiseerde fasiliteit, gedoen moet word.
Eksperimente is uitgevoer in twee fases: nie-lineêre en lineêre toetse in die
Hoogspannings (HV) laboratorium. Die nie-lineêre toetse word gedoen om die
kleinste-benaderde-afstand (MAD) af te lei en die lineêre eksperimente word
gebruik om FEKO (‘n numeriese elektromagnetika simulasie program) met die
metings omgewing te kalibreer. Sodra daar ‘n korrelasie tussen die lineêre data en
die gesimuleerde data is, kan daar aangeneem word dat die simulasie model en die
toets-opstelling betroubaar is. Die simulasies kan dan gebruik word om 'n
meetkundige faktor te bepaal as 'n bydrae tot F. Rizk se voorspellings vergelykings.
Die Rizk vergelykings word gebruik om die veilige vlieg sones langs die OHTLs te
beskryf. Dit kan dus gebruik word as ‘n toevoeging tot die nie-lineêre
eksperimentele werk. Saam met die normale meet standaard voorstellings, is die
Rizk voorspellings geformuleer sodat dit die lyn spesifieke oplossings kan bepaal.
Die voorgestelde verklarings waardes word in per eenheid waardes beskryf, wat dan
gekies kan word met ooreenstemmende historiese lyn data.
Kraglyn-vonke word ondersoek om die lyn-bestraling verskynsel beter te verstaan.
Hierdie begrip kan in die lyn inspeksie proses en in die uitleg van kraglyne naby
radiostilte-areas help. Kennis van OHTL bestralings patrone kan help met die
identifisering van corona en vonk-bronne tydens die inspeksie proses. 'n UAV met 'n aangehegte spektrum analiseerder is gebruik om die lug-vonkende
metings te neem. Vonk vlakke wat gemeet is word dan gebruik om 'n Numeriese
Elektromagnetiese (CEM) model te bevestig. Die CEM model kan dan gebruik word
om OHTL bestralings eienskappe verder te ondersoek.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/85795 |
| Date | 12 1900 |
| Creators | Groch, Matthew |
| Contributors | Reader, H. C., 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 | Unknown |
| Type | Thesis |
| Format | xxvii, 153 p. : ill. |
| Rights | Stellenbosch University |
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