Control systems and automation
T
he energy transmission and distribution industry is evolv-
ing. For switchgear customers, distribution automation and
environmental responsibility are now high on the agenda,
alongside the traditional requirements of performance, reliability,
safety and cost.
As the lifetime of switchgear is often 30 years or more, technology
research and development (R&D) must be innovative and pragmatic
- meeting demands for automation and load-related growth, while al-
lowing for the refurbishment of, and integration with, existing assets.
The smart grid distribution network is a critical goal for utilities in
helping to manage our electricity needs – now and in the future. Utili-
ties have an increasing need to understand the load on their network
and improve their ability to share the load in real time between dif-
ferent networks in order to minimise the disruption of power supply.
The ultimate aim is to improve reliability, to increase efficiency and
capacity, to help reduce energy wastage. Our job, as a specialist in
secondary distribution solutions, is to develop the next generation
technology that will help utilities to meet this goal.
Just 15 years ago switchgear could only be manually managed
on-site. Now, utilities with SCADA (Supervisory Control and Data
Acquisition) systems have extensive control over transmission, and
increasing control over distribution equipment from remote locations.
The goal of distribution automation is real-time adjustment to
changing loads, generation, and failure conditions of the distribu-
tion system, without operator intervention. By providing a better
understanding of network loading and an opportunity to manage the
varying load quickly, by controlling field devices remotely, distribution
automation technology is becoming increasing attractive to utilities
and network operators beginning major smart grid deployments.
Indeed, global spending on intelligent electricity distribution
systems rose 7% last year to reach $13,9 billion. Further steady 10%
growth is expected to see the market worth $25,2 billion by 2018 [1].
Despite this potential, a utility’s number one challenge remains
justifying the business case; the scope, complexity and costs of the
IT investments necessary means each step of deployment requires
careful cost-benefit analysis. It is critical, therefore, that switchgear
being developed and deployed today is automation ready, ensuring
easy integration with existing networks, while not compromising
future smart grid developments.
Furthermore, as switchgear has long lifecycles, many utilities
currently have a significant installed base of ring main units (RMUs)
designed in late 1980s. Most of these RMUs were not designed for
automation and could not be motorised for remote automation and
control. As such, utilities have two options: either to replace the old
equipment with new at high capital cost, or extend the life of current
equipment by automating it.
Lucy Switchgear has designed a solution to upgrade installed
switchgear with actuators and Gemini Remote Terminal Units (RTU)
to enable remote operation and control, thereby creating significant
savings for utilities and network operators. This is universally recog-
nised as a more financially viable option than completely updating
the infrastructure with brand new technology, without compromis-
ing the quality and safety of the public or the operator, or lowering
delivery efficiency.
Environmentally responsible RMUs
Albeit high up the priority list, enabling smart grids is not the only
concern of utilities and network operators at the moment – envi-
ronmental responsibility is also rising up the agenda. In switchgear
technology, SF6 (Sulphur Hexafluoride) gas has replaced oil and air
for electrical insulation and arc interruption in most new and retrofit
RMU installations due to its excellent electrical insulation and non-
corrosive properties.
SF6 is a greenhouse gas, and there are some environmental con-
cerns around using it in switchgear. Specifically, during arc extinction,
SF6 gas is incinerated, producing toxic by-products which require
special precaution while dismantling and recycling the switchgear.
However, if SF6 gas is used in conjunction with vacuum bottles then
the arc breaking is done by a vacuum breaker and SF6 is therefore
only used as an insulating medium. This method of arc breaking of-
fers a clean solution with no by-products.
Plus, if the gas tank is designed in such a way that it is resistant
to corrosion and can keep the SF6 gas pressurised throughout the
whole lifecycle of the switchgear, then the SF6 gas can be recovered
and recycled for reuse. This reduces the impact of SF6 on environ-
ment, while utilising the inherent insulating properties of the gas.
Safety
RMUs are generally used in distribution substations, which are often
close to, or sometimes located within, populated areas. Therefore, the
Enabling the smart
grids of the future
By S Singh, Lucy Switchgear
It is critical that switchgear being developed and deployed today is automation ready, ensuring easy integration with existing networks, while
not compromising future smart grid developments.
Electricity+Control
July ‘13
22
