LINE IMPEDANCE TESTING KIT
STS family accessory for line impedance test
- Optional line impedance testing kit for STS 5000 and STS 4000
- The kit is made of:
- The option allows performing the measurement of: soil resistivity, ground grid resistance, step and touch tests
- STSG protects the operator against possible high voltage spikes
STLG- line and grid module
STSG – safety grounding module
LINE IMPEDANCE TESTING KIT
The line impedance testing kit is made of:
- STLG – line and grid module
- STSG – safety grounding module
The line impedance test has the purpose of verifying the computed value of the Earth coefficient KL for the HV overhead lines.
This is a critical parameter for the setting of a distance relay: a wrong value causes the false fault location.
STLG line and grid module
The option allows performing both the measurement of: soil resistivity, ground grid resistance, step and touch tests, and of:
overhead lines zero sequence and mutual coupling coefficients.
This option applies to STS 5000 and 4000 models.
Unless for soil resistivity, for these tests the device is connected to an out-of-service overhead line. Tests are performed with AC current; so, the total impedance is too high for the STS current or voltage generators. STLG is a high power transformer, which increases the output current. A high current switch allows selecting the desired current range. A voltage meter displays the generated voltage. The option takes its power from the EXT.
BOOSTER connector of STS. Output current and voltage are metered and sent back to STS measuring inputs; a third output allows STS to know the selected range.
Device characteristics are the followings.
- Input: from STS 5000, via the booster connector.
- Output current ranges: 10, 20, 50, 100 A AC.
- Output power: 1800 VA steady; 5200 VA peak for 10 s.
- High current range selector switch.
- Analogue output voltage meter. Meter range: 600 V AC.