Abstract
This article provides a diagram of a sequence filter on sealed contacts with windings for electrical installations with a delta phase configuration. The theoretical framework is given for arranging protection, executing the current shut-off functions and sequence filters. The choice of filter parameters and methods for vector plotting that characterize its behavior are proposed. It describes a calibration method of filter-combined current on sealed contacts for an electrical installation with conductors located at the corners of an equilateral triangle. A protection feature calculation method based on determining the coordinates of sealed contacts close to a triangular phase structure is developed. The calculation by the triggering feature of the conventional overcurrent protection is offered. An example of the protection trigger settings selection and the sensitivity verification is described.