Abstract: The invention relates to a method, a computer program and a device (20) for the plausibility checking of current transformers (7) in an electrical switchgear assembly (1) and to a switchgear assembly (1) having such a device (20). According to the invention, zones (1a, 1b, 1c) bounded by current transformers (7) and possibly by open switches (3-5) are detected for an instantaneous topology of the switchgear (1), in each zone (1a, 1b, 1c) the signed current measurement signals are added and in the case of significant deviations of the current sum from zero, all current transformers (7) of the associated zone (1a, 1b, 1c) are identified as being problematic. Exemplary embodiments relate to, among other things: a warning counter (2e) for problematic current transformers (7); in the case of a defective current transformer (7), an operation with calculated currents or an automatic combining of zones (1a, 1b, 1c); and coordinating the plausibility test with switching actions.

Abstract: The invention relates to a method, a computer program and a device (20) for the plausibility checking of current transformers (7) in an electrical switchgear assembly (1) and to a switchgear assembly (1) having such a device (20). According to the invention, zones (1a, 1b, 1c) bounded by current transformers (7) and possibly by open switches (3-5) are detected for an instantaneous topology of the switchgear (1), in each zone (1a, 1b, 1c) the signed current measurement signals are added and in the case of significant deviations of the current sum from zero, all current transformers (7) of the associated zone (1a, 1b, 1c) are identified as being problematic. Exemplary embodiments relate to, among other things: a warning counter (2e) for problematic current transformers (7); in the case of a defective current transformer (7), an operation with calculated currents or an automatic combining of zones (1a, 1b, 1c); and coordinating the plausibility test with switching actions.

Abstract: The present invention is directed to a method for determining actual tripping characteristics with the aid of a test apparatus in which test parameters are input with the aid of an input unit. The aim is to specify an appropriate method which works particularly quickly and precisely. This can be achieved when a theoretical tripping characteristic of the respective protective relay is stored in the test apparatus. Each measurement point of the actual tripping characteristic is determined on a locating straight line, the starting point for the measurement being a point of intersection of the locating straight line with the theoretical tripping characteristic. In this case, the locating straight line dissects the theoretical tripping characteristic at an angle. The angle is situated in a range from 60.degree. to 120.degree., 90.degree. being preferred.