Electricity + Control February 2019

Figure 1 (left): The equipment, including 3 000 m of cable from LAPP, was transported through ice and snow up the slopes of the Hekla volcano in Iceland.

CABLES + ACCESSORIES

Source: Icelandic Meteorological Office

The goal is to discover how eruptions are reflected in the measurement data.

in summer. The aim, however, is to keep overall energy consumption as low as possible. The cable was supplied by Johan Rönning, the market leader for electrical equipment in Iceland. Johan Rönning imports and sells LAPP products in Iceland, and supplies electrical components to most geophysical installations. The company has been working with LAPP since 1985.

metal cylinders contains a mass made from a thermally stable metal alloy. This is kept virtually motionless by means of an electronic feedback loop. Tremors in the ground cause the housing to vibrate, while the mass does not follow the motion due to its inertia. The position of the mass relative to the housing is measured and the feedback loop executes a magnetic or electrostatic counterforce, depending on the model. The voltage required to generate this force is the measurement value that is digitally recorded. This makes it possible to de- tect movements of just a few nanometres (1 nano- metre = 1 millionth of a millimetre). As Hekla offers so little warning time, it is not possible to save the measurement values in the seismometer and take readings on site every few months as is usually done. Instead, they must be communicated immediately. This system usually occurs via 3G mobile modems, but is not possi- ble in this instance for all six seismometers as the modem requires up to 5 W of electrical power. In the gloomy Icelandic landscape, where the sun only rises for a few hours a day, if at all in winter, solar cells cannot provide enough energy. And this is why Möllhoff’s team decided to use a cable from LAPP to transfer the data.The cable transfers data, and the energy required to run the seismometers, which is generated by three independent small wind turbines. Each wind turbine is supported by a solar cell to compensate for periods of low wind

“We are very happy with the coop- eration”, says Óskar Gústavsson, key account manager at Johan Rönning. Gústavsson praises the excellent support from LAPP’s experienced experts, adding: “They’re also fantastic with delivery times”.

Figure 3: Conditions at the peak of Hekla, almost 1 500 m above sea level, place special demands on the material.

Source: Icelandic Meteorological Office