Electronic research and development house, Netshield SA has released a new third-generation managed and isolated surge protection system (SPS) that replaces mechanical circuit breakers and incorporates power condition monitoring and SNMP management.
The new SPS addresses shortcomings in conventional surge protection methodologies which, according to Netshield MD Inus Dreckmeyr, often provide users with a false sense of security.
“Many organisations found this out the hard way with the recent spate of load shedding which sometimes resulted in power literally surging back,” he says.
“Another problem occurs when electricity in a building trips as a result of a power surge and someone simply flips the trip switch to restore power. While it may appear that everything is back to normal the power protection unit could have failed, and the next surge comes that along could pass right through the ‘clamp’ and destroy vital equipment."
In addition, lightening strikes can be just as devastating as induced surging from switching loads on the power grids. These can be carried into the building via electrical wiring, telecommunications lines and antenna. Where surge protection is applied, it usually involves placing a protection device on a line. The device will simply clamp the line to prevent the surge from passing through to the equipment being protected.
This works well – once and possibly twice. Most of these units are designed to absorb only a certain amount of energy. Once that level is reached, the unit fails. The problem is that no one knows when or if a unit has failed until equipment is damaged.
Netshield, therefore, has long taken a different approach to surge protection. “What many regard as the most important defence against surges is just a first line of defence for us. We apply a second defence and not a single failure jump has been reported in more than a decade,” Dreckmeyr says.
The new Netshield SPS incorporates a 2U mountable unit that is AC powered and is designed to protect the user’s mains from the lightning and surges which would typically occur on the input 220V on a 19” cabinet. Optional data protection modules for external telecoms data lines like x.21, Ethernet, ADSL and E1 are also available.
The SPS has a manageable port though which the user can configure and read a variety of settings via the SNMPV1 protocol. Limits like voltage upper and lower limits can be set up. When the unit’s parameters are “Out of Limits” the unit will automatically send SNMP traps to a designated IP address to indicate alarm conditions.
The user can also switch the mains on or off, set the site name, time, date or check the serial number and version of the unit via the SNMP.
At the back of the SPS is a RS485 bus to which the user can connect up to two high power probes.
The Netshield high power probe with its high surge handling capability, over-current fusing and a re-setable current trip setting, provides a mains surge protecting solution for users in the telecoms, commercial and industrial industries. The probe has a manageable interface and it can be configured and managed either remotely or on-site via the ‘Netshield Sensor Protocol’.
An onboard tactile switch allows the user to switch the mains on or off and clear the accumulative power usage (kWh).
Another optional enhancement for the SPS is an Automatic Power Failover Switch (APFS) which provides a solution during power outages when power needs to be fed automatically from a secondary source like generators or solar panels.
The APFS can work as a stand alone unit or in conjunction with the Netshield SPS. In standalone configuration, the unit will sense the normal mains and switch over to the secondary source when a failure occurs or when the primary source is not stable.
Using the “Netshield Sensor Protocol” the user can configure or read remotely the APFS settings such as manual switch over, or statuses such as generator diesel level.
If configured for generator mode, the AFPS unit is able to sense the diesel level of the generator, determine how long the generator has been running and see when last the generator was serviced. The user is also able to manually switch the generator on and off, and switch over to the primary or secondary input power source.
When configured for solar panel mode, the unit can sense the battery pack power level and determine whether or not it is safe to switch over to the solar panel.
On the LCD of the SPS unit, the user can check almost all the statuses of the unit and available high power probes connected on the RS485 bus. The user can see the time, date, site name and the power information of the units and probes. When the user connects data protection modules, those statuses also are available on the LCD.
For enhanced protection, the SPS can also be combined with medium and coarse externally mounted devices, including a medium protection NLVALEPLUG. This hot swappable electrical sub-distribution board DIN-rail mounted device absorbs nominal discharge surge currents of up to 20KA. These boards are normally installed on each floor of larger buildings while a single distribution board is usually sufficient for smaller buildings.