Electricity + Control January 2017

EARTHING + LIGHTNING PROTECTION

Safe Energy Control Simplifies Surge Protection

Dipl.-Ing. (FH) Florian Lenzmeier, Phoenix Contact GmbH & Co

The Safe Energy Control (SEC) product range offers high performance and a long service life for lightning and surge voltage protection.

cause, in our example, there are already a PLC (Programmable Logic Controller) and various telecommunications equipment near themain distributor, the LT-SEC-T1+T2 lightning/surge voltage arrester combi- nation has been selected here (see sidebar text 1). Since the main dis- tributor is already protected by amain fuse (F1 = 315 gG), the lightning arrester requires no additional back-up fuse in this case.Type 1 arresters from the SEC range require no additional back-up fuse up to 315 A. In applications with higher rated current, either an additional back-up fuse or the FLT-SEC-Hybrid – a combination of a fully-enclosed spark gap and an integrated surge-current resistant back-up fuse – can be used. Sub-distributor Because the nearest floor or sub-distributor is located far away from the main distributor in this example, the use of a type 2 surge voltage protector is required. The VAL SEC surge voltage protector is a suitable choice. As with type 1 protectors from the SEC range, this device can be used in ap- plications that are protected up to 315 A without an additional back-up fuse. Because the device is one of the slimmest surge voltage protection devices on the market, the installer saves bothmoney and space. In our example, a three-phase TN-S network can be protected over less than three horizontal pitches – or less than 50 mm. Protecting the end device The type 3 surge voltage protector is installed right in front of the end device to be protected – in this case, the production system control- ler and robot arm. The PLT-SEC surge protector is being used. The main advantages of this device are its convenient installation and universal use. That is because type 3 products from the SEC range are equally suitable for use in ac and dc applications. An additional back-up fuse in single-branch configuration is unnecessary because all PLT-SEC devices come with pre-installed, built-in back-up fuses.

A basic prerequisite for optimal building protection is a universal concept that takes all measures necessary to protect against surge voltage into account. Whether a building is a small single-family home or a vast industrial complex is more or less irrel- evant. The array of lightning and surge voltage protectors, structured in tiers, must be well-conceived and precisely implemented. While the use of a type 1 lightning protector varies according to a number of different environmental parameters, the use of type 2 and 3 surge protection is necessary in all cases. Industrial building The implementation of a surge protection concept demonstrates the advantages of the newSafe Energy Control (SEC) product range. The components from this series allow multi-level protection concepts for commonly used installations to be easily imple- mented. The example used describes the planning process on the basis of a simplified building concept. This scenario details the protection of an end appliance – in this case, an automated production system – in an industrial building. The machine and building’s power infeed is supplied via a three-phase 230/ 400 V TN-S system. The various end devices in this industrial building are supplied with power through several sub-distributors. In addition, the building is equipped with an external Lightning Protection System (LPS). Main distributor Because of the external LPS, a corresponding interior LPS is also required. To meet this requirement, a type 1 lightning current arrester must be installed right where the power line enters the building. Be-

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