DEVICE FOR DIAGNOSING THE CONDITION OF HIGH-VOLTAGE BUSHINGS Russian patent published in 2023 - IPC G01R31/08 G01R31/12 

FIELD: high voltage electrical equipment; control and measuring equipment.

SUBSTANCE: invention relates to control and measuring equipment in the field of high voltage electrical equipment and is intended for continuous monitoring of insulation, diagnostics and protection of high-voltage bushings of high-voltage devices, such as power transformers, autotransformers and reactors. Essence: the device, according to the invention, implements periodic measurement of instantaneous values of voltages at the inputs and leakage currents of the input insulation (by the number of phases), temperature and humidity of the environment, with subsequent calculation of the sine and cosine components of voltages and currents at the first harmonic, their amplitudes and phase relationships between currents and voltages, calculation using these values of the capacitances of the main insulation of the bushings and loss factors (tg δ), calculation of deviations of the obtained tg δ values and capacity from their normal values for given measured values of temperature and humidity of the environment and the formation of warning and/or alarm signals when the specified deviations exceed the specified limit levels. The device contains, according to the number of phases of the apparatus, devices for connecting to the object, connected to the measuring terminals of the inputs, nodes for protecting current circuits, connected to the outputs of the connection devices, nodes for galvanic isolation and normalization of current signals, connected to the outputs of nodes for protecting current circuits, nodes for normalizing voltage signals receiving signals from a network voltage transformer, an ambient temperature sensor, an ambient relative humidity sensor, a first six-input analogue-to-digital converter, the inputs of which are connected to the outputs of voltage and current normalization units, a second two-input analogue-to-digital converter, the inputs of which are connected to the outputs of temperature sensors and ambient humidity, and a microcontroller containing a block for calculating the current values of capacitors and tg δ of inputs connected to the output of the first analogue-to-digital converter, a block for calculating normal capacitance values and tg δ of inputs at given ambient temperature and humidity, connected to the output of the second analogue-to-digital converter, block for setting threshold values of capacitances and tg δ of inputs, the input of which is connected to the output of the block for calculating normal values of capacitances and tg δ of inputs, comparison block connected by two inputs to the output of the block for calculating the current values of capacitances and tg δ of inputs and to the output of the block for setting threshold values of capacitances and tg δ of inputs, a discrete output block, the input of which is connected to the output of the comparison block, and discrete warning and alarm signals (protection) are generated at the outputs, and a serial communication port for transmitting the current values of all measured and calculated parameters to the operator’s computer terminal.

EFFECT: increased accuracy and sensitivity of the device.

5 cl, 7 dwg