Earth/Ground Tester

Procedure of Measurements

reliable values, the instrument offers the possibility of averaging over a longer period.

1.Select a fixed frequency (see "Control loop", Operation)

2.Keep the "START TEST" button pressed until the warning "measured value unstable" disappears. Max. averaging time is approx. 1 min.

Measurements on High Voltage Pylons

Measuring the Earthing Resistance without Disengaging the Overhead Earth Wire Using the Selective Clamp Method

The measurement of the earth resistance of a single high voltage pylon usually requires the overhead earth wire to be disengaged (lifted off) or the seperation of the earthing system from the pylon construction. Otherwise false reading of the resistance of the pylon earth electrode are liable to occur because of the parallel circuit of the other pylons connected to each other by an overhead earth wire.

The new measuring method employed in this instrument - with its external current transformer to measure the true current flowing through the earth elec- trode - allows measurements of earth electrode resistances without disconnec- tion of the earthing system or disengaging the overhead earth wire.

As all four pylon stubs are connected to the foundation earth of the pylon, the measuring current Imeas is divided into five components according to the pre- sent resistances involved.

One part flows via pylon construction to the overhead earth wire and further to the parallelly circuited pylon earthing resistances.

The other four current components (I1... I4) flow via the individual pylon foots.

The addition of all currents result in a current IE going through the earthing resistance, i.e. the resistance of the "composite"earth electrode to the soil.

If the current transformer is fixed to each pylon stub, one after the other, four resistances have to be measured which show a behaviour inversely propor- tional to the corresponding current components I1 ... I4. The feeding point of the measuring current is to be left unchanged to avoid a change in the current distribution.

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Fluke 1625 user manual Measurements on High Voltage Pylons
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1625 specifications

The Fluke 1625 is a versatile and essential tool in the realm of insulation testing, primarily aimed at electricians, maintenance professionals, and equipment specialists. Throughout its design, Fluke has incorporated a range of features and technologies intended to enhance testing efficiency, accuracy, and user experience, making the 1625 a standout choice for those in need of reliable insulation measurement tools.

One of the key features of the Fluke 1625 is its ability to perform insulation resistance testing with several voltage settings. The device offers test voltages of 250V, 500V, and 1000V, making it adaptable for different applications, including low-voltage and high-voltage systems. This flexibility is paramount in ensuring that technicians can perform tests on a wide variety of electrical systems without needing multiple devices.

The 1625 also boasts an impressive insulation range of up to 4 GΩ, providing the capability to measure insulation resistance accurately across a spectrum of installations. A notable technology integrated into the unit is the automatic discharge function, which ensures that any stored energy in capacitive components is safely released after testing, enhancing the safety of operations.

Furthermore, the Fluke 1625 includes a patented 'Insulation Diagnostic' feature that assists users in identifying problematic areas in an electrical system. This feature helps professionals determine whether insulation is adequate, helping to prevent potential failures, accidental shorts, and system downtimes.

In addition to insulation resistance testing, the Fluke 1625 also supports other functionalities, including continuity testing and low-resistance measurements. This multi-functional capability streamlines operations, allowing technicians to conduct multiple tests without switching devices, resulting in increased productivity.

The device is designed with user-friendliness in mind, featuring an intuitive interface complete with large buttons and a clear display. This makes it easier for users to navigate through different testing modes and review results. To further enhance usability in challenging environments, the 1625 has a rugged, durable design, ensuring it can withstand the rigors of job sites.

Another significant characteristic of the Fluke 1625 is its ability to log test results for further analysis. It can store up to 99 datasets, which can be later reviewed or downloaded for reporting purposes. This data management capability is crucial for maintaining records, fulfilling compliance requirements, and improving operational efficiencies.

In conclusion, the Fluke 1625 is a robust and comprehensive insulation tester that incorporates essential features and advanced technologies. With its versatility, safety mechanisms, and user-friendly design, it stands out as an indispensable tool for electrical professionals committed to ensuring system reliability and safety.
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