Surge protection for the power supply of the E-Plus basis stations
E-Plus has established on the German mobile phone market as an innovative company and in many business areas is a pioneer for the complete industry range. This bears much responsibility which E-Plus is facing continuously. One aspect is not to rest on ones laurels but have the courage to follow new paths.
Application
The E-Plus network based on the GSM 1800 standard is known for its excellent language quality. To achieve a network covering of more than 98% of the German population numerous base stations (BTS) are necessary. Good radio prerequisites are necessary for the construction on exposed sites, like for example on elevations, tower buildings and on towers or poles. With increased expansion and due to the high danger potential lightning protection and thus over voltage protection is becoming more relevant for Cost-intensive engineering and the demand for permanent availability of the network operation are making a protection concept indispensable. E-Plus and Phoenix Contact jointly established a protection concept for the power supply.
Mobilfunkantennen in exponierter Lage
Protection for the basestation
Mobile phone base stations frequently are installed on guest buildings. For such installations surge protection devices are installed not only directly in front of the base station, but also in the meter area in order to grant the supply here, too. Part of the base station, in UMTS network (3rd generation) it is called Node B, are system engineering (transmitting and receiving engineering), aerial engineering and its electrical supply. Special attention in the selection of the surge voltage components is paid to the maintenance of the power supply and thus the continuous availability of the base station. Since the start of the GSM 1800 network of E-Plus the power supplies of mobile radio installations are reliably protected against over voltages by combinations of lightning arresters type FLASHTRAB and surge voltage arresters type VALVETRAB.
The operating means in the meter area have a sufficient insulation resistance, so that lightning arresters type FLASHTRAB provide sufficient protection.Since 2001 E-Plus basic stations are equipped with arresters which are operating according to the AEC (Active Energy Control) principle that was developed by PHOENIX CONTACT. AEC means active energy control between lightning current and surge voltage arrester. The response voltage of an applied lightning arrester FLT 35 CTRL-0,9 of 900 V is pre-adjusted by trigger electronics. Lightning and surge voltage arresters thus can be switched parallel. In combination with the surge voltage arrester VALVETRAB VAL-MS 230 a class I-/class II-arrester combination has been realised which fulfils all lightning protection classes on a maximal overall width of 140 mm (3+1-circuit in TN-/TT-systems).
Allround Support
In close cooperation a protection concept has been developed that corresponds to the technical specifications of E-Plus. Beside the selection of the arresters suitable for the application purpose, an additional support includes recommendations for EMC-suitable constructions of electric sub-division (EUV) used in the area of basic stations. An electric sub-division constructed according to these recommendations was tested in the in-house lightning current test laboratory.
Result
With the appropriate selection of surge protection devices the availability of the complete radio/transmit-receive system is increased and the quality of the available services is secured. The use of arresters working according to the AEC principle enable a compact electric sub-division which protects the power supply of a mobile radio basic station efficiently and economically against lightning overvoltages.