Method and microprocessor device for determining the distance to the short-circuit location

Abstract

The invention relates to a method and a microprocessor device for determining the distance to the short-circuit location in highly branched medium-voltage distribution networks, as well as in high-voltage overhead transmission networks. The microprocessor device implementing the method establishes a relationship between the distance to the short-circuit location and the impedance of the transmission line, measured at the point where a relay protection with an integrated distance-to-fault function is installed. A microprocessor device for determining the distance to the short-circuit location, implementing the method, consists of a main board on which are mounted: a power supply module (3), an input module for analog quantities (1) connected to an analog-to-digital converter (2). The analog-to- digital converter (2) is connected to the power supply module (3) and the microcontroller system (4). The display (6) is connected to the power supply module (3). The microprocessor system (4) is connected to the binary outputs (5), the LAN (7), and the RC234 / 485 (8).

Description

[0001] METHOD AND MICROPROCESSOR DEVICE FOR DETERMINING THE DISTANCE TO THE SHORT-CIRCUIT LOCATION

[0002] I. FIELD OF THE ART

[0003] The invention relates to a method and a microprocessor device for determining the distance to the short-circuit location in highly branched medium-voltage distribution networks, as well as in high-voltage overhead transmission networks.

[0004] The microprocessor device implementing the method establishes a relationship between the distance to the short-circuit location and the impedance of the transmission line, measured at the point where a relay protection with an integrated distance-to-fault function is installed.

[0005] IL PRIOR ART

[0006] From the state of the art, methods and devices are known for detecting and measuring the distance to the short-circuit location and faults in the power transmission network.

[0007] Patent document CN 116106688 A discloses a device and a system for detecting a short circuit in the power transmission system. The device includes a first winding located on a bus, a current generation circuit configured to be electrically connected to the first winding and to generate current on the bus and the housing of the short-circuit fault detection device, as well as to output a triggering signal in the event of a short-circuit fault on the bus.

[0008] Patent document CN205539319 (U), published on 31.08.2016, discloses a device for detecting faults in the operation of the power network. The device includes a microcontroller, a short-circuit sensor, a fault analysis and localization module, a voltage transformer, and a current transformer.

[0009] From patent document CN 113253049 A, a device and method are known for measuring the distance to the fault in a power distribution network. The device comprises a sensor unit connected to the power transmission line, a distance-measuring device, a microcontroller for data processing and fault diagnosis, a wireless communication module, and a display module for visualizing the readings. Through this method, the fault is assessed and the exact distance is measured. The method uses time-domain reflectometry with spread spectrum technology and a radar signal cross-correlation algorithm.

[0010] III. TECHNICAL ESSENCE OF THE INVENTION

[0011] The objective of the invention is to determine the distance to the short-circuit location in branched distribution networks of overhead power lines.

[0012] This objective is achieved with a method for determining the distance to the short-circuit location, which comprises the following operations: an operating voltage of 220 V is supplied to a microprocessor device. Input information is received from voltage transformers with rated primary voltages of 20 kV and rated secondary voltages of 100 V, as well as from current transformers with rated secondary currents of 5 A or 1 A. A pulse is supplied from the starting elements of the relay protection, as well as from an external signal provided to a digital input.The microcontroller system sets internal configurations for inputs / outputs of various functions and selects time characteristics; it sets and stores the line parameters in non-volatile memory, provides galvanic isolation on all inputs and outputs to protect against various interferences, stores the date and time of the short-circuit occurrence and its duration. By changing certain parameters, it recalculates the distance to the short-circuit location. By modifying the settings, calculations are carried out again, after which the calculations are repeated with the previously recorded data, and this is stored as a new short circuit. It eliminates errors arising from parameter-input settings of the line, selects optimal settings based on the results of short circuits with the determined actual distance, measures and indicates the current phase currents and voltages, records the data in a format suitable for digital oscillography of the input signals, and automatically uses them in a software product for detailed analysis. An interface transmits the fault data to a personal computer for adjusting the settings.

[0013] A microprocessor device for determining the distance to the short-circuit location, implementing the method, consists of a main board on which are mounted: a power supply module, an input module for analog quantities connected to an analog-to-digital converter (ADC) module. The ADC module is connected to the power supply module and the microcontroller system. A display is connected to the power supply module, and the microprocessor system is connected to binary outputs, to LAN, and to RC234 / 485.

[0014] IV. EXPLANATION OF THE ATTACHED FIGURES

[0015] • Fig- 1 - Block diagram of the microprocessor device.

[0016] • Fig. 2 - Structural diagram of the microprocessor device.

[0017] V. EXEMPLARY EMBODIMENT OF THE INVENTION

[0018] A microprocessor device for determining the distance to the short-circuit location in highly branched medium-voltage distribution networks, as well as in high-voltage overhead lines, implementing the method, consists of a main board on which the following components are mounted: a power supply module (3), an input module for analog quantities (1) connected to an analog-to-digital converter (ADC) module (2). The ADC module (2) is connected to the power supply module (3) and the microcontroller system (4). The display (6) is connected to the power supply module (3), while the microprocessor system (4) is connected to the binary outputs (5), the LAN (7), and the RC234 / 485 (8).

[0019] VI. PRINCIPLE OF OPERATION

[0020] The device is powered by an operating voltage of 220 V via the power supply module (3). Input information is received from voltage transformers with rated primary voltages of 20 kV and rated secondary voltages of 100 V, as well as from current transformers with rated secondary currents of 5 A or 1 A.

[0021] Start-up is performed by sending a pulse from the starting elements of the relay protection, as well as from an external signal provided to a digital input. The values of the short-circuit currents and voltages, scanned at a predefined frequency, are recorded in a cyclic buffer. The calculationsfor determining the distance to the short-circuit location are made based on the recorded current and voltage data in memory.

[0022] The microprocessor device performs the following operations:

[0023] • Setting internal configurations (inputs / outputs of various functions, selection of time characteristics);

[0024] • Setting and storing line parameters in non-volatile memory;

[0025] • Galvanic isolation of all inputs and outputs for protection against various interferences;

[0026] • Storing the date and time of the short-circuit occurrence as well as its duration;

[0027] • Possibility of recalculating the distance to the short-circuit location by changing certain parameters. This function allows the operator, after a short-circuit event, to recalculate by altering some settings and then repeat the calculations with previously recorded data. The result is recorded as a new short circuit. This feature is convenient and makes it possible to correct errors in line-parameter settings and to select the optimal settings based on short-circuit events where the actual distance is known;

[0028] • Measuring and indicating the current phase currents and voltages;

[0029] • Recording data in a format suitable for digital oscillography of the input signals, as well as automatically using them in the Matlab software product for detailed analysis;

[0030] • Continuously measuring the electrical parameters of the input analog current and voltage signals;

[0031] • Providing an interface for transmitting fault data to a personal computer and modifying settings.

[0032] The microprocessor device can operate in two modes, by enabling or disabling the protection. In the case where triggering occurs from the starting elements of the relay protection, there will be available information for faults outside the considered transmission line. In the mode where triggering is based on the measuring elements of the protection, the device will operate only if the short circuit is on the considered line.

Claims

PATENT CLAIMS1. A method for determining the distance to the short-circuit location, characterized by comprising the following operations: an operating voltage of 220 V is supplied to a microprocessor device; input information is obtained from voltage transformers with rated primary voltages of 20 kV and rated secondary voltages of 100 V, and from current transformers with rated secondary currents of 5 A or 1 A; a pulse is supplied from the starting elements of the relay protection, as well as from an external signal provided to a digital input; the microcontroller system sets internal configurations of inputs / outputs of various functions and selects time characteristics, sets and stores the line parameters in non-volatile memory, ensures galvanic isolation of all inputs and outputs for protection against various interferences, stores the date and time of the short-circuit occurrence and its duration, recalculates the distance to the short-circuit location by changing certain parameters, and by modifying the settings, performs calculations again and then repeats the calculations with previously recorded data, storing the result as a new short circuit. It eliminates errors arising from line-parameter settings, selects the optimal settings based on short-circuit events with a known actual distance, measures and indicates the current phase currents and voltages, records the data in a format suitable for digital oscillography of the input signals, and automatically uses them in a software product for detailed analysis. An interface transmits the fault data to a personal computer to modify the settings.

2. A microprocessor device for determining the distance to the short-circuit location, implementing the method, consisting of a microcontroller system and a display, characterized in that a main board is equipped with a power supply module (3), an input module for analog quantities (1) connected to an analog-to-digital converter (ADC) (2). The ADC (2) is connected to the power supply module (3) and the microcontroller system (4). The display (6) is connected to the power supply module (3). The microprocessor system (4) is connected to the binary outputs (5), the LAN (7), and the RC234 / 485 (8).

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