Business Units / FAQ
Our most Frequently Asked Questions are below, but we can also be contacted here if you would like any further information or have any other questions, please get in touch with us.
- Does remote isolation align with existing site procedures?
Yes. The system is flexible enough to function and align with existing site isolation procedures. Additional features can also be provided with the system functionality that may be required to maintain compliance. REMSAFE personnel provide assistance with the site document updates if required.
- Does the RIS incorporate a “Try Step” / “Try Start” / “Try Test”?
The “Try Step” is an optional feature as some site preferences prefer to call up control for a “Try Start”.
- How does it verify an isolation?
The verification is the summary of isolator status, position, energy sensing and try start amongst other functions to confirm and verify the isolation. Only when the isolation is completely verified by the safety function is the isolation lockout switch released. It can be then be turned to the isolated position to allow the operator to attach their lock.
- What is the difference between conventional and safety relays?
Safety relays are designed in such a way that, if wired correctly, neither a fault in the device nor an external fault caused by the sensor or actuator will lead to the loss of the safety function. Each circuit contact has a mirror or monitoring contact that are physically connected also referred to as positively guided.
- How are the device and energy presence sensing conditions monitored?
The sensors are connected to the safety PLC inputs. The conditions are constantly monitored to ensure they match the expected state, any discrepancy causes an alarm and prevents the isolation process from being completed until rectified.
- How does the RIS replace the requirement for visual confirmation of isolator status?
All isolation status conditions are available to the operator on the field display. The integrity of the various sensors and contacts is calculated to ensure it reaches the reliability level required.
- How does the Remote Isolation System actually isolate?
The Isolation is initiated via the operator interface panel in the Field Isolation Station (FIS). The FIS is mounted adjacent to the plant to be isolated. The operator requests the isolation from the FIS, the control room operator approves via SCADA and the isolation process commences. The isolators are automated and moved into the isolated position. Electrical isolations are whole current; that is the main supply to the drive is disconnected, not control power. Mechanical isolators such as valves are also automated and moved to the isolated/closed position. The presence of energy and the position of the isolators is monitored prior to and during isolation. Once the isolation is verified the Isolator Lockout Switch actuator lock is released enabling the switch to be rotated to the isolated position. A hasp/scissor/clasp can be placed and then a personal isolation lock applied.
- How many locks can the switch support?
The system is designed to operate up to 100 individual isolators per application. These isolators can be locked out at a single location at the Isolator Lockout Switch on the Field Isolation Station (FIS) with a single personal isolation lock per person. The personal isolation lock/hasp hangs off the Isolator Lockout Switch’s lockout point. For larger group isolations, a group lockbox would be used with just one group lock on the FIS Isolator Lockout Switch.
- What are the location options for FIS units – for example, can we have it at the bottom of a staircase, a long way from the actual drives?
The client can have as many FIS units as desired, located wherever you wish, the only requirement being that these just require power and access to the communications network.
- What happens during a power outage?
If the power goes off when an isolation is in place, this has no effect on the isolation. When power is restored the isolation will still be in place as expected.
Should power be already off before isolating, remote isolation would not be available, so a conventional isolation would still be required.
- What is the lifespan of the system?
Nominally 20 years. Updates and upgrades are available for the duration of the systems existence.
- How are variable speed drives isolated?
Typically VSDs are isolated upstream. The DC bus voltage can be monitored to ensure the drive has no capability of turning the motor even after the power supply has been removed. Where Safe Torque Off is available on a particular drive model, this can be used instead of the upstream isolation.
- How do you integrate RIS with older switchgear?
This varies between applications. Generally HV isolators with integral truck racking is utilised and controlled by the remote isolation system. Other methods are to use safety functions on variable speed drives if available or the installation of an automated HV isolator in series with the existing switchgear. LV isolations are via the REMSAFE Failsafe Instrument Cubicle where automated isolators are accommodated and connected in series between the existing MCC isolator and the drive.