POWER ENGINEERING JOURNAL

VOL. 13, NO. 4, AUGUST 1999



Electrical engineers for 186
the future - whose
responsibility?
by Doug Warne


Working plant and 188
systems harder
by Michael Baker


Modern steels for 190
transformers and machines
by Philip Beckley
Electrical machines depend on ferromagnetic
materials to handle useful power within a
practical compass. Flux magnification and control
lies at the heart of machine efficiency. Reduction
of thickness, perfection of purity and improved
grain texture are some of the ways forward.
Streamlined standardised loss measuring systems
can produce benefits for all.


Quantitative reliability 201
analysis of distribution
systems: automation
by D. M. Rigler, W. R. Hodgkins and
R. N. Allan
Great importance is attached to improving the
performance of the electricity distribution
network by reducing the number of interruptions
and the time during which customers are off
supply. This article reviews some of the means
which are used to bring about these
improvements and considers in particular the
potential benefits that may be achieved by
automation. The results of an analysis are used to
illustrate the level of improvement which may be
achieved.


Letters to the Editor 205


The need for engineering 207
training, experience and
management in the ESI
by Dennis Nunns
Failure to recognise the effects of the changed
operating conditions and carry out reinforcement
of the network wlien needed resulted in tlie
breakdown of the four llOkV cables supplying
the Central Business District ofAucldand.


Research Grants 211

TUTORIAL

High-frequency load- 21 3
resonant DC-DC converters
by A. J. Forsyth
This tutorial is
concerned witli one
type of resonant DC-DC
convener in which the
loadlorinsparlola
continuously oscillating
resonant circuit. The
operating principle and
device switching
aveforms are first
examined; a common
analysis method is then
used to derive and
compare the
characteristics of the
two principal converter
topologies,

Contracts & orders 221

nanoHertZ 222