DE896225C - Capacitive voltage divider for high-voltage power converter systems - Google Patents

Description

Capacitive voltage divider for high-voltage power converter systems In Converter systems for very high voltages, such as those used for power transmission with high-voltage direct current come into question, you need for measuring purposes, for Actuation of display devices and relays true-to-curve images of the voltage processes. Voltage dividers must be provided for this purpose. You can now for example the high-voltage capacitors used in such systems for other purposes thereby train simultaneously to voltage dividers that one with the high voltage capacitor connects a low-voltage capacitor in series with a correspondingly large capacity. The voltage drop that occurs across this low voltage capacitor becomes that mentioned above Apparatus supplied.

Part of the voltage to be monitored now consists of any shape AC voltages on which DC voltage elements are superimposed.

While the alternating voltage components are in the capacitive voltage divider to divide in the ratio of the reciprocal values of the capacities is the division of the DC voltage components given by the leakage resistances of the capacitors.

However, the leakage resistances are per unit of capacity for the different capacitor types very different; they are also for the same capacitor type subject to major fluctuations, in particular depending on the operating time.

The invention now provides a way of avoiding these difficulties at. It affects you capacitive voltage divider for high-voltage power converter systems. According to the invention, by connecting an ohmic or inductive in parallel Resistance to the measuring capacitor derived the direct voltage element and the measuring circuit a corresponding DC voltage element is artificially supplied again. The resistance to divert the DC voltage element must be small in relation to the diverting resistances of the capacitor, so that the capacitor and resistor are connected in parallel resulting DC voltage component can be neglected. On the other hand, Idarf this resistance cannot be made arbitrarily small, otherwise the mapping of the The desired tensioning process is no longer true to the curve. If you use the Deriving the DC voltage link an inductive resistance, it must Inductance can be very large in order to cause the circle measuring capacitor parallel inductance to oscillate to avoid.

The suppressed DC voltage is added with a special Device generated and fed to the measuring or relay apparatus. The DC voltage elements are generally not constant, but depend on the modulation of the converter. Should now be the voltage tapped at the low-voltage capacitor or also limited Excerpts from the same are compared with a target value, it is useful to as, DC voltage source between the tapping capacitor and the measuring or relay apparatus to use a controllable auxiliary rectifier, which depends on the modulation of the main converter is controlled (coupled with the rotary control of the main converter or controlled directly with the same control pulses as the main converter).

Claims (2)

PATENT CLAIMS: I. Capacitive voltage divider for high-voltage converter systems, characterized in that by parallel strings of an ohmic or inductive Resistance to the tap capacitor derived from the direct voltage element and the A corresponding DC voltage element is artificially fed back into the measuring circuit. 2. Arrangement according to claim I, characterized in that for generation of the DC voltage element is controlled in the same direction as the main converter Auxiliary rectifier is used.