Substations for DC power supply have rated powers as high as the upper single-digit MW range. Substations and the grid sections they supply must be effectively safeguarded against short circuits. The protection mech-anism must reliably interrupt high levels of current as they occur, limiting the power that flows into the short circuit.
The protective device must measure the current and voltage in order to execute algorithms for short-circuit detection. This requires high voltage transducers that mea-sure quickly and precisely while withstanding high loads. They must master voltages be-tween 750 and 3000 V DC, including tempo-rary surges in the case of energy recovery for braking trains, for example.
Our high voltage transducers meet the requirements for measurement and signal processing: VariTrans P 41000 for current measurement via shunt resistor and VariTrans P 42000 for direct voltage measurement up to 3000/3600 V DC.
The use of highly insulating solids – includ-ing solid casting – ensures reliable galvanic isolation. The circuit design is dimensioned for quick, high-precision signal transmission. The transducers are extremely resistant to external fields and common-mode disturb influence.
This avoids false-positive short-circuit detec- tion (traction power supply interruptions without short circuits), which is another significant yet undesirable disruption of operations.
VariTrans P 41000 and P 42000 have prov-en their value in DC traction power supply substations worldwide. You’ll be playing it safe with the two measuring devices. A comprehensive evaluation of their years of use found that the mean time between two failures (MBTF) is 2,165 years.