Title: Protective circuit arrangement for a high-voltage capacitor bank

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Claims: What is claimed is:

1. In a protective circuit arrangement for a high voltage capacitor bank, including at least two equal branches containing individual capacitors connected in parallel and on one side to a phase of the network system, a current measuring device being arranged in series with each of the branches for measuring the current therein, with the outputs of the current measuring devices provided to a differential protection device, the output of which is coupled to a monitor, an improved differential protection device comprising:

a. a first differential protection relay having first and second inputs and an output;

b. first and second highpass filters coupling the first and second inputs of said first differential protection relay to the current measuring devices in the two branches;

c. a second differential protection relay having first and second inputs and an output;

d. first and second lowpass filters coupling the first and second inputs of said second differential protection relay to said two current measuring devices;

e. storage means coupled to the output of said first differential protection relay;

f. an AND gate having as inputs the output of said storage means and the output of said second differential protection relay;

g. time delay means having its input coupled to the output of said AND gate and providing an output which is delayed to appear a predetermined time after its input appears; and

h. wherein the output of said first differential protective relay and the output of said time delay means are coupled to the monitor.

Other info:

Inventors: Becker, Michael (Uttenreuth, DT)

Application Number: 623113
Filing Date: 1975-10-16
Publication_date: 1976-10-05
Assignee: Siemens Aktiengesellschaft (Munich, DT)
Primary Class(es): 361/17 307/105, 361/87, 361/110
Other Classes:
US Patent Ref:

3319120	May, 1967	Fahlen	317/12.
3486073	Dec, 1969	Eriksson et al.	317/53.
3515943	Jun, 1970	Warrington	317/53.
3735250	May, 1973	Masui	317/27.
3909672	Sep, 1975	Lundquist et al.	317/12.

Other Refs:
Primary Examiner: Miller, J D
Assistant Examiner: Salce, Patrick R.
Attorney: Kenyon & Kenyon Reilly Carr & Chapin