Early identification
of faults on rail
signalling power
systems driven by
new standards
ony Edwards, Industrial
Sales Manager at Bender UK
has specific responsibility
for the rail sector, looks at
how increasing demands
for more effective identification of faults
is shaping more sensitive and responsive
monitoring.
T
Every day rail maintenance crews face
the challenge of ensuring that the power
systems for operating signalling systems
are free from faults to ensure that there is
no interruption of service.
Faults inevitably occur due to a natural
degradation of the infrastructure or other
common causes such as rodent damage or
water ingress.
The maintenance teams are set targets
to rectify those faults – but they can only
be achieved by deploying technology
which helps them to identify earlier and
more accurately where those faults are
occurring.
The ideal scenario is technology which
gives them early warning of faults which
are not yet critical – providing a breathing
space to plan and deliver predictive and
preventative maintenance solutions.
The new standard for those products from
June 2017 is detailed in the Network Rail
Level 2 Product Specification: Insulation
Monitoring and Fault Location Systems for
use on Signalling Power Systems. It sets
out Network Rail’s vision for Insulation
Monitoring Devices (IMDs) and Insulation
Fault Location Systems (IFLS) comprising
their system requirements, network
monitoring architectures, and IMD and
IFLS capabilities along with requirements
for portable models, and the integration
of devices with Network Rail’s Intelligent
Infrastructure systems.
The document explains that the changes
are designed to drive the development
of new technology to provide additional
parameters, for example capacitance to
assess the safety of the Signalling Power
System and further reduce the risk of
electric shock. It also states that it wants
to improve detection of signalling power
cable failure before it interrupts a power
supply leading to loss of signalling,
and improve the ability to pinpoint the
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position of faults to drive reductions
in time and the disruption caused by
signalling power cable faults.
Network Rail believes better monitoring
will ultimately drive reductions in OPEX
and CAPEX costs, enable the deployment
of alternatives to more expensive auto
reconfiguration systems, and extend the
life of existing cables and networks.
Bender UK is currently the only UK supplier
with approved products to meet this
requirement and the company has worked
closely with its principal contacts at
Network Rail to shape the development of
the technology to meet the new standards.
One of the key requirements is the need
for enhanced sensitivity to narrow down
the area where a fault is occurring. Bender
has responded with the new upgraded RS4
integrated insulation monitoring and earth
fault location system.
It is more sensitive that the widely
deployed RS3 and enables ‘first fault’
location (100 kilo ohms) before the
fault becomes critical. It also measures
capacitance, voltage and frequency
delivering more information to help assess
the health of the system.
The insulation monitoring device within
RS4 enables fault location at Tier 3
electrical syste m network level for the
signalling system. It has proved very
effective in meeting the ‘Red’ requirements
within the standard, which must be
complied with and achieved at all times.
Earth Fault Location is the effective
solution for sub-network Tier 2 monitoring
to assist in locating the fault on a circuit,
a key element in the Amber requirements
within the new standard.
The RS system continually monitors
insulation values to show real time status
of the power system. When the insulation
value (IR) drops, the system records the
fault and the Bender units put a test
current signal or pulse into the system
which is pulled to earth at the point where
a fault exists.
The new RS4 unit is much smaller and
more compact to make it easier to
incorporate in the panels serving systems
operating at a lower power rating.
Later this year, a variant will be available
tested and ready for easy ‘plug and play’
installation and commissioning alongside
existing power infrastructure systems up
to AC650V.
Integration of RS4 devices with Network
Rail’s Intelligent Infrastructure systems is
achieved by incorporating GSM-enabled
data loggers equipped for real time
communication to deliver immediate
notification of insulation faults which are
identified by the system.
Once the fault has been identified on a
specific circuit, the portable EDS 3090
case is used in the field to pinpoint the
location trackside by monitoring the
pulse on the cable. In line with the new
standard Bender has made significant
improvements to the EDS 3090 unit which
has more sensitive clamps and receiver
technology.
The unit is self-powered through
connection to the trackside signal
electrical network. It delivers live
monitoring of the system status to
immediately indicate if there is an earth
fault and the status of the insulation. The
portable unit can also be used to provide
independent verification of the RS system
performance.
The new RS4 is just part of the huge
Bender rail offering which includes power
quality meters, insulation monitoring
devices and monitoring software for
rolling stock, signal power, points heating
and trackside use.
For more information, contact Tony
Edwards: [email protected]
or call Bender UK on 01229 480123