Various conventional measurement methods are used in soil resistivity measurements. In general, in all conventional methods, four measuring piles are nailed to the soil at different intervals on one line. Specially developed measuring devices are used for measurements at small intervals, and voltmeter ammeter method is used for measurements at large intervals.
If a transformer or power station is to be built on any land, the first task is to determine the soil's self-resistance on that land. Measurements are usually performed using the Megger device. With this study, the shape and location of the grounding electrons to be connected to the grounding network to be installed under the substation or substation are determined. Where grounding electrodes are to be buried, it is very important that the specific resistance of the soil is at very low levels and that it will also protect this feature for years. Therefore, specific resistance measurements are those that should be repeated in the long term. Measurements should be made for at least five years in the summer and winter season on the land where the electricity installation will be established.
In the electrical internal installation control: branch, energy room, cable shaft, meter and distribution panels, junction boxes, sockets and lighting are reviewed on the basis of the relevant legal regulations, standards and regulations. Among these procedures, control with a thermal camera is very important. Thermal cameras, which are remote measurement devices, detect the heat emitted by objects as a result of the malfunction, convert it into electronic signal and reflect it as a thermal image. In this way, the problematic area is determined and necessary precautions are taken before it causes more serious damage. Panels and parts that may be heated are checked and reported with a thermal camera. It is checked whether the leakage current protection relays in the facility and the facility work properly, and whether their opening currents and times are suitable or not. Unfortunately, ground resistivity is generally not measured in these tests.
Soil specific resistance or specific soil resistance means the resistance of a cube of soil with essentially 1 meters on the edges. Resistance values naturally vary from soil to soil. It is possible to make resistance measurements of all conductors in nature. In addition, these values are generally constant. However, the soil gives different results because of the extremely variable variables. The flow through the soil passes through a large surface. Therefore, the current density in grounding systems is quite high. The depth of the flow depends on the specific resistivity of the soil. If the ground specific resistance is not too high, it is possible for the current to travel on the surface or deeply. In the meantime, soil specific resistance has a very close relationship with temperature and humidity. If the soil moisture content is high, its specific resistance decreases. Similarly, if the temperature is high, the specific resistance drops. Swamps are the soil with the lowest specific resistance. In swamps, resistance is around 30 ohms, on clay soils it is around 100 ohms and on stony soils it is around 3000 ohms.
Our company conducts specific resistance measurements in accordance with the relevant legal regulations, standards and test methods published by local and foreign organizations within the framework of electrical safety inspections.
