RU2741063C1 - Current protection device with mathematical analysis function - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering and can be used on railway transport for protection of equipment of traction rolling stock (TRS) or multiple-unit train (MUT) against short circuits and overload in electric networks. Current protection device comprises switching module, which includes measuring sensor on Hall effect or measuring shunt and electromagnetic relay or contactor, control module, which includes an analogue-to-digital path, consisting of voltage divider, operational amplifiers, filters and analog-to-digital converter, microcontroller, switchboard control circuit, a power converter, a nonvolatile memory microcircuit chip and a data line driver chip. As a result, control module controls switching devices and provides measurement, preservation and analysis of current function in time.

EFFECT: monitoring of rate of change of current function in time, preventing failure of external equipment.

4 cl, 2 dwg

Description

The invention relates to electrical engineering and can be used in railway transport to protect equipment of traction rolling stock (TPS) or multiple unit rolling stock (MVPS) from short circuits and overload in electrical networks.

A known device is a current protection device (patent No. 2706421 RU), containing a phase conductor, a neutral conductor, power contacts with a shunt release coil, a current sensor connected to the third input of the microcontroller, a load, a power supply, an amplification organ connected to the first output of the microcontroller, a voltage sensor connected to the first input of the microcontroller, a voltage sine-wave zero crossing sensor connected to the second microcontroller input, a current zero-crossing sensor connected to the fourth microcontroller input, an electrical network state indicating body connected to the second microcontroller output. As a result, in the microcontroller there is a continuous algorithmic processing of the incoming values and the allocation of current increments in the electrical network. Based on the calculated values of the current increment and the power factor of the electrical network, the microcontroller gives a signal to disconnect the load after a time delay or instantly.

The disadvantage of this device is the lack of analysis of the mathematical function of direct current based on the accumulated data on the values of the current increment.

The closest in technical essence to the proposed device is a device for intelligent current protection of electrical networks against single-phase earth faults (patent No. 2715909 RU), containing on each line a zero-sequence current sensor and a relay element of the protection unit connected to it at the input with a set setting for operation , a functional module for calculating the indicator of incompleteness of an earth fault, a voltage measuring transformer, a module for automatic adaptive correction of the setting current for protection operation, containing a set of sensors for monitoring environmental parameters.

The disadvantage of this device is also the lack of analysis of the mathematical function of direct current, which does not allow analyzing the history of any event that caused the transition of the system to a protective state.

The technical objective of the invention is to eliminate the systemic shortcomings of the equipment and control algorithms as a result of the analysis of the mathematical function of the current in time, which makes it possible to find patterns in the algorithm of the locomotive operation and transitions to the protective mode.

The technical result is achieved by the fact that a current protection device with a mathematical analysis function contains a switching module including a Hall effect measuring sensor or a measuring shunt and an electromagnetic relay or contactor, a control module including an analog-digital path consisting of a voltage divider , operational amplifiers, filters and analog-to-digital converter, microcontroller, switching device control circuit, power converter, non-volatile memory microcircuit and data transmission line driver microcircuit.

The proposed device performs the following functions:

- measurement of DC or AC current flowing in the circuit, voltage measurement and storage of measured values in non-volatile memory;

- mathematical analysis of the function of voltage and current in the circuit:

- analysis of the dynamics of changes in the magnitude of voltage and current ripples;

- analysis of the dynamics of changes in current or voltage;

- calculation of the frequency spectrum of current and voltage signals;

- control of external or internal circuit switching devices according to commands received from the communication line;

- automatic removal of voltage from switching devices in case of violation of the conditions described by the software algorithm.

FIG. 1 shows a block diagram of a current protection device with a mathematical analysis function.

The device consists of a switching module that performs the function of switching external electrical circuits, as well as converting the current value into an output voltage using Hall effect sensors or a measuring shunt, and a control module that controls switching devices and provides measurement, storage and analysis of current and voltage functions. in time.

The switching module includes a Hall effect measuring sensor 1 or a measuring shunt (selected based on the level of the flowing current in the analyzed circuit) and an electromagnetic coil 2.1, which controls the normally closed and / or normally open contacts of the relay (contactor) 2.2.

The control module includes an analog-to-digital path 3, consisting of a voltage divider, operational amplifiers, filters and an analog-to-digital converter, a microcontroller 4, a switching device control circuit 5, a power converter 6, a non-volatile memory chip 7 and a data transmission line driver chip 8 CAN or RS485 interfaces.

The overcurrent protection device with the function of mathematical analysis can be configured to perform a transition to the protective state of the switched circuits by programmatically setting the thresholds for this event - in absolute or relative value. FIG. 2 shows various graphs of the stream function in time, corresponding to: a - avalanche-like growth of current; b -exponential current growth; c - slow current growth; d - slow decrease in current. The device allows you to set the window function of the current, and thus allows you to notify any diagnostic or control function about the rate of change of the parameter, thereby preventing the failure of any external equipment.

In this case, you can programmatically adjust the sampling step of the input measured current and voltage signals. Three values will be recorded in the nonvolatile memory of the block: time stamp, current and voltage values. Writing to the memory will be performed continuously cyclically, while an array of points corresponding to the transition of the external switched circuit to the protective state, which can only be cleared by the service personnel, will be stored in a certain memory area. The length of the memory sections and the width of the saved fragments are determined by the program configuration of the block.

Claims (4)

1. A current protection device with a mathematical analysis function, containing a switching module that includes a Hall effect measuring sensor or measuring shunt and an electromagnetic relay or contactor, a control module including an analog-to-digital path consisting of a voltage divider, operational amplifiers, filters and an analog-to-digital converter, a microcontroller, a switching device control circuit, a power converter, characterized in that a nonvolatile memory microcircuit is included in the control module, which allows storing measurements of voltage and current flowing in DC or AC circuits with their subsequent analysis by a microcontroller, and a driver microcircuit data transmission line, through which the diagnostic or control function is notified of the rate of change of parameters, thereby preventing the failure of the external equipment of the locomotive or electric train. 2. The device according to claim 1, characterized in that it allows calculating the frequency spectrum of the current and voltage signals. 3. The device according to claim 1, characterized in that it allows analyzing the dynamics of changes in the magnitude of voltage and current ripples. 4. The device according to claim 1, characterized in that it allows analyzing the dynamics of changes in current or voltage.

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