23 March 2018
The consequences of an arc flash can include significant damage to switchgear, conductors and the switchboard. The worst consequence of such electrical faults is the injury or death of electrical maintenance staff who frequently work within electrical switchrooms.
To help reduce the effects of a low voltage switchboardarc flash, NHP and Terasaki have developed the Arc LogiX system.
The Arc LogiX system uses the concept of ‘active circuit breaker suppression’. Potential arc flash incident energy is reduced by automatically adjusting down the short circuit protection settings of the incoming Air Circuit Breakers (ACBs).
Arc LogiX operating principle
To minimise the damage that an arc flash can cause to a switchboard, the incoming circuit breaker must be set to detect and clear the arc fault within an optimum timeframe.
AS/NZS 3000:2007 clause 18.104.22.168 outlines how to adjust and configure incoming circuit breakers protection settings to limit the damaging effects of an arc flash. This approach is called ‘active arc flash suppression’.
The foundation of the Arc LogiX system is ‘active arc flash suppression’.It works by automatically implementing a temporary protection setting ‘maintenance mode’ within the incoming ACBs before people can enter the switchroom.
This ‘maintenance mode’ reduces the circuit breaker instantaneous short circuit ‘pick up’ setting to its lowest level, therefore providing optimum fault clearance time and minimal damage during an arc flash.
Circuit Breaker clearance time counts
To limit the destructive effects of an arc flash it is vital to disrupt and clear the fault as quickly as possible. The time delay in clearing the fault is directly linked to the sensing and tripping speed of the circuit breaker.
The Arc LogiX system utilises the Terasaki TemPower 2 ACB which can clear a short circuit fault in less than 30ms thanks to its patented double break contact design. 30ms is the fastest total short circuit clearance time available from any ACB on the market today.
Independently tested and verified to reduce dangerous arc flash incident energy
NHP has conducted arc fault testing at an independent NATA certified laboratory which has proved the effectiveness of the Arc LogiX system.
The documented test results confirm a significant reduction in the destructive arc fault energy released within the switchboard when compared to using ‘normal’ protection settings.
With the Arc LogiX system it is possible to reduce incident energy released during an arcing flash, potentially reducing the level of PPE required to be worn by electrical staff while working in the low voltage switchroom*.
*Arc flash study should be undertaken by a recognised professional to confirm the arc flash energy levels and the recommended PPE.
Choose the right system
Arc LogiX is a fully assembled NHP system that is available in a basic ‘Plus’ version or an advanced ‘Premier’ version. Installation into the switchroom and wiring to the Terasaki TemPower 2 ACBs is to be undertaken by an electrical contractor. The Plus model provides system activation using a simple key switch.
The Premier model is the advanced system that is activated via an integrated touchscreen which is mounted on the front of the controller unit**. The touchscreen not only allows system activation, but it visualises the core energy management measurements, protection settings, trip and alarm events of the connected ACBs. SMS activation and warning message functionality are standard.
** HMI can be mounted separate to the controller enclosure as a special request
Key Benefits of Arc LogiX
- Greatly reduces the danger to people and damage to infrastructure caused by an arc flash
- Easy to use by maintenance workers
- Validated method of arc flash mitigation as outlined in AS/NZS 3000:2007 clause 22.214.171.124
- Performance confirmed by a NATA approved Australian test laboratory
- Full system visibility via integration in SCADA or BMS systems
- Suitable for use with many older Terasaki TemPower 2 ACBs
- Flexible cost investment as Arc LogiX has a basic model which can be upgraded to an advanced model
- Ideal for installation during an ACB retrofit