Vol.106 (1) March 2015 SOUTH AFRICAN INSTITUTE OF ELECTRICAL ENGINEERS 1

March 2015

Volume 106 No. 1www.saiee.org.za

Africa Research JournalISSN 1991-1696

Research Journal of the South African Institute of Electrical EngineersIncorporating the SAIEE Transactions

Vol.106 (1) March 2015SOUTH AFRICAN INSTITUTE OF ELECTRICAL ENGINEERS2 � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �� � � � � � � � � � � � � � � � � � � � � � � � � � � � � �� � � � � � � � � � � � �Mrs Gerda Geyer

South African Institute for Electrical Engineers (SAIEE)

PO Box 751253, Gardenview, 2047, South Africa

Tel: (27-11) 487-3003

Fax: (27-11) 487-3002

E-mail: researchjournal@saiee.org.za

� � � ! " # $ % & ' ( ' ) ' & * $ & ' $ + + & " $ , - ' � $ * # ' , ' * * $ & .� / 0 1 2 3 4 5 5 6 7 8 1 0 0 4 9 0 : 0 ; 4 5 � 1 4 4 � < / 1 2 � / 4 5 4 � / 2 ; = : 6 / > � 3 � / 4 < 6 3 3 ? @ 4 4 / / 4 A 1 4 B 4 9@ / 1 : / 0 : � 2 2 4 @ 0 � > 2 4 < : / @ 6 7 3 1 2 � 0 1 : >0 - ' C " % % " ) # D " & D $ # * $ ! " # * - $ ( ' % * ! ' � 5 � 1 4 4 � C & , $ / ' * ' $ & , - = " E & # $ % C " & $ F * ! & $ , ! " # + E & + " * ' * GINSPEC (The Institution of Electrical Engineers, London); ‘The Engineering Index’ (Engineering Information Inc.)

H I J K L M N O P I M H Q J H R H M NS T U V W X Y U Z Y [ \ U ] ^_ ` a b c d c e c f g h i j k l, Faculty of Engineering and the Built Environment, e m Z m n U Z n ] T U V W X_ ` a b c o c o p q r g

, Faculty of Engineering and the Built Environment, o _ ] [ U m f U o V ] T U V W X o[ a s s j q p h g l p a q t g q u o p v q g w _ ` a h k t t p q v x_ ` a b c f c _ c f p q u kUniversity of Pretoria, SA _ ` a b c o c e g r g ` g yUniversity of Pretoria, SAT ` W c \ a w w g q u

, Centre for Telecommunications Research, London, UK_ ` a b c ^ c V g z g { p ` g, School of Electrical and Information Engineering, _ ` a b c m c | c \ g q } p q h zT ` ] c n a w a ~ p q t

Pretoria, SA[ a s � j l k ` � U q b a ` s g l p a q o � t l k s t g q u o a b l { g ` k ] q v p q k k ` p q v xT ` e c � k t l t l ` g l k �Newco Holdings, Pretoria, SA_ ` a b c m c ~ g q u k ` e k ` { k

T ` [ c ~ g q u k ` � g w lResearch, Pretoria, SA._ ` a b c d c T { a w g l � z �[ a q l ` a w g q u m j l a s g l p a q xT ` d c � j z t k w_ ` a b c V c ~ g q Z p k z k ` z] w k h l ` a s g v q k l p h t g q u m q l k q q g t x_ ` a b c | c \ c [ w a k l k_ ` a b c V c | c W c m b j w w a_ ` a b c X c n k t h r z k] w k h l ` a q T k ~ p h k t g q u [ p ` h j p l t x_ ` a b c e c u j _ w k t t p t

University of Pretoria, SAT ` T c ^ a l �, Gilgamesh Associates, LLC, Vermont, USA] q k ` v � g q u _ a { k ` o � t l k s t x_ ` a b c e c T k w p s g `] q v p q k k ` p q v g q u V k h r q a w a v � e g q g v k s k q l x_ ` a b c | Y \ c _ ` k l a ` p j t

, Faculty of Engineering and the Built Environment, _ ` a b c f c _ ` k l a ` p j tPretoria, SA

] q v p q k k ` p q v p q e k u p h p q k g q u d p a w a v �_ ` a b c | c | c \ g q k z a s �University of Pretoria, SA _ ` a b c ^ c X g l l g � �

Vienna University of Technology, Austria_ ` a b c d c d a q r g s � University of California, San Francisco, USAn k q k ` g w V a � p h t � ] u p l a ` t Y g l Y w g ` v k xT ` _ c | c [ p w w p k ` t �_ ` a b c e c m c ~ g q � � z

, School of Electrical and Information Engineering, U Z V ] X Z m V U W Z m f _ m Z ] f W ^ X ] } U ] � ] X oW.A. Brading, New Zealand

The University of Birmingham, UK

Prof. J.A. Ferreira, Electrical Power Processing Unit, Delft University of Technology,

The Netherlands

Technical University of Darmstadt, Germany

C.F. Landy, Engineering Systems Inc., USA

Prof. D.A. McNamara, University of Ottawa, Canada

Clemson University, USA

R.T. Waters, UK

T.J. Williams, Purdue University, USA_ j � w p t r k u � �South African Institute of Electrical Engineers (Pty) Ltd, PO Box 751253, Gardenview, 2047

Tel. (27-11) 487-3003, Fax. (27-11) 487-3002,

E-mail: researchjournal@saiee.org.za

� � � � � � � � � �Dr Pat Naidoo� � � � � � � � � � � � � � � �Mr André Hoffmann

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