HV Transmission line and tower inspection safe-fly zone modelling and metrology

Groch, Matthew (2013-12)

Thesis (MEng)-- Stellenbosch University, 2013.

Thesis

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.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/85795
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