OVR40150SP datasheet(4/62 Pages) ABB

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Surge

otective

Devices

16.2

Low Voltage Products & Systems

1SXU000023C0202 Rev. A

ABB Inc. • 888-385-1221 • www.abb.us/lowvoltage

What is a transient surge?

A transient surge is a sudden (shorter than a millisecond) rise in the flow of power. Voltage can peak at 12x the nominal system voltage.

Transient surges result from a number of sources, the most common of which are internal, such as load switching

and even normal equipment operations. In fact, approximately 80% of transients are generated internally. External

transients are the result of lightning and load switching by utilities and upstream facilities.

Internal load switching

Switching on/off any elements that create a sudden variation of load will also cause a sudden change in current flow

and generate transient surges.

Lightning strikes

A lightning strike (direct or indirect) can have a destructive or disturbing effect on installations located up to several

miles from the actual point of the strike. During a storm, underground cables can transmit energy from a lightning

strike to equipment installed inside buildings.

A lightning protection device (such as a lightning rod or Faraday cage) installed on a building to protect against the risk

of a direct strike can increase the risk of damage to electrical equipment connected to the main power supply near or

inside the building.

The lightning protection device diverts the high strike current to ground, considerably raising the potential of

the ground close to the building on which it is installed. This causes overvoltages on the electrical equipment

directly via the ground terminals and induced via the underground supply cables.

Switching effects on power distribution

The switching of transformers, motors or inductances in general, variation of load, disconnection of circuit

breakers or cut outs lead to overvoltages that penetrate a building. The closer the building is to a generating

station, substation or upstream switching point, the higher the overvoltages may be.

Facilities and operations left unprotected are highly susceptible to the damaging effects of transients.

Such as:

• Catastrophic equipment failure

• Immediate operation shutdown

• Long term disruption of business

• Expensive equipment repair and replacement

• Data losses, system resets and network down time

In order to ensure protection from transient surges, installation of surge protective devices (SPD) is a must.

ABB has a long history of engineering and manufacturing quality surge protective devices. This brochure will

provide all the information needed to select the proper products to begin protecting any facility or operation.

ABB’s family of surge protective devices include the following:

• OVR NE12 enclosed SPD for service entrance locations

• OVR DIN rail AC SPD for equipment protection

• OVR PV DIN rail DC SPD for photovoltaic installations

• OVR DIN rail data line SPD for sensitive communications networks

General information

Introduction

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