New ABB service helps win the relay retrofit race
08 February 2015
ABB has launched a new approach to replacing time-served relays in power distribution networks that reduces the time required from around a month to only one hour.
The ABB Relay Retrofit Programme is targeted at the vast global base of SPACOM relays installed for the protection and control of medium voltage (MV) switchgear in DNO (distribution network operator) and industrial power networks.
Many of these relays are now 30 years old, and the ABB service enables them to be replaced by state of the art IEC61850 compliant Relion 615 IEDs (intelligent electronic devices), bringing the switchgear into the modern age and significantly extending its operational life.
A further advantage is that the Relion IEDs offer additional functionality such as the built-in arc-fault protection capability that is increasingly important for oil and gas installations.
In the conventional relay replacement approach, engineers must identify as many as several hundred parameters for the old relay and transfer them across to a new unit. Installing the new unit into the space designed for the old has its own challenges.
Furthermore, thorough testing and commissioning is then needed to identify any errors in transferring the parameters before the replacement is complete. An operator with 100 relays could be looking at more than eight years of effort. And with an installed base of 700,000 SPACOM relays worldwide, ABB recognised that a new method was needed.
The new one-hour process
By exploring the logic of its relays and creating a set of software and installation tools, ABB has created its relay retrofit programme. In this new approach, ABB’s engineer arrives on-site with the new IED, a pre-prepared set of wiring, a software tool and all the tools and equipment needed to install the new relay within an hour.
Once on-site, the relay’s low voltage (LV) compartment is de-energised and secured. The engineer will then connect the old IED to a migration support tool loaded onto a laptop. This takes a perfect copy of the parameters of the existing IED and transfers them over to configure the new IED – a step that can be achieved in just a few minutes.
A set of ready-made wiring supplied with markings that correspond to both the existing and the new IED means that wiring can be transferred quickly and accurately from old to new, again within just a few minutes.
Fitting the new IED into the existing panel is straightforward using a customised set of tools to extend the cut-out in the panel if the new IED is larger than its predecessor. If it is smaller, a pre-prepared cover plate will cover the gap that is left by the old unit and fit around the new IED perfectly.
Moving on to testing and commissioning, an ABB Relion test box, testing template and test device bring together all the tools to test and commission the new IED in an easy and reliable manner.
In total, retrofitting a single relay will only take around one hour, with no risk of error or surprises as the parameters have been transferred digitally rather than manually.
New for old
To date, ABB has explored the logic of some of the most commonly installed IEDs that it supplied up to 30 years ago. These include models from the SPAJ 140 series of overcurrent and earth fault relays, the SPAM 150 C motor protection relay and the SPAU 130 C overvoltage and undervoltage relay. All of these can be replaced with relays from the Relion 615 range of IEDs.
These are both future proof with native IEC 61850 compliance and interoperable with legacy systems. They have standard configurations and an extensive set of ethernet and serial communication options.
An important aspect of the Relion 615 units is their plug-in design that speeds up installation, maintenance and testing, and allows the cases to be installed and wired before delivery.
The benefits of the approach are clear. By upgrading relays to IEC 61850 compliant Relion 615 models, operators will bring their protection and control systems into the modern age, therefore extending the life of the switchgear.
In addition, by using a process that delivers the upgrade in a fraction of the time of the conventional approach, replacing relays has become something that an operator can now consider seriously. Using the conventional approach, a programme of replacing relays would represent a major investment in both time and money.
Fast acting arc-flash protection
A further benefit of retrofitting with the Relion 615 IEDs is that they come with additional functionalities such as integrated three-channel arc-fault protection. This technology, which is particularly relevant for critical switchgear installations, such as in the oil and gas industries, protects the switchgear against arc faults by minimizing the burning time of the arc, thus preventing excessive heat and damage.
This minimises material damage and allows power distribution to be smoothly and safely restored. As older switchgear is more prone to arc faults, an arc protection system can effectively extend the life of switchgear further enhancing the return on investment.
Time is critical when it comes to detecting and minimising the effects of an electric arc. An arc fault lasting 500 ms may cause severe damage to the installation. If the burning time of the arc is less than 100 ms the damage is often limited, but if the arc is extinguished in less than 35 ms its effect is almost unnoticeable.
Generally applied protection relays are not fast enough to ensure safe fault clearance times at arc faults. The operation time of the overcurrent relay controlling the incoming circuit breaker may, for instance, have been delayed to hundreds of milliseconds for selectivity reasons. This delay can be avoided by installing an ABB arc protection system. The total fault clearance time can be reduced to a maximum of 6 to 8 ms plus the circuit breaker’s contact travel time.
In addition to installing the Relion 615 IED, all that is required to implement arc-fault detection is to install the appropriate sensors that detect the intense light produced by a developing arc fault.
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