RU150078U1 - EXPLOSION-PROTECTED MINE STARTER - Google Patents

Abstract

1. Explosion-proof mine starter containing a flameproof enclosure, divided into two compartments with an explosion-proof wall, a switch-disconnector is installed in one compartment, a withdrawable unit is installed on the other, on which a vacuum contactor, transformer, current and voltage sensors, chokes and other switching elements are installed, two outlets and one inlet compartment adjoin the case, two covers, one of which is quick-open, on the inside of which there is an indication unit and a protection unit and control detecting, comprising an interface with external systems, scheduling, characterized in that the protection and control unit is a separate module and a removable module pamyati.2. Explosion-proof mine starter according to claim 1, characterized in that the protection and control module protects the connection from overload depending on the nature of the load by selecting the type of protective characteristic - normally inverse, very inverse or extremely inverse. 3. Explosion-proof mine starter according to claim 1, characterized in that the withdrawable unit is connected to the disconnector using a multi-contact system.

Description

The utility model relates to the safe use of electricity in coal mines, as well as in explosive rooms, the atmosphere of which may contain combustible gases and vapors that have explosive properties in a mixture with air.

An explosion-proof magnetic starter is known (USSR Author's Certificate No. 1174566, class E21F 9/00, 1985), made in an explosion-proof housing divided into a contactor compartment and a disconnector compartment, with disconnector, control and protection equipment housed therein. The compartments are covered with lids, on the top of the case are the input and output boxes.

A disadvantage of the known starter is the use of several separate units for the implementation of protection, namely, the remote control unit for the control unit, the overcurrent protection unit MTZ, the thermal protection unit for the connections of the overhead protection device, the insulation control unit of the BKI, each of which is subject to periodic inspection and calibration, which increases the dimensions of the unit protection, complicates the maintenance process and reduces the reliability of the starter. A disadvantage of the known starter is also the lack of an information communication channel with a unified automatic control system (ACS), and the lack of memory devices for creating an event archive, which significantly limits the functionality of the starter in modern operating conditions.

Known explosion-proof magnetic starter (USSR author's certificate No. 1470978, class E21F 9/00, 04/07/89. Bull. No. 13), made in an explosion-proof housing containing a disconnector, contactor, sensitive elements, blocks BDU, MTZ, BKI, TZP and power supply, control unit with an indication unit connected to it.

The disadvantage of this starter is the presence of several separate protection units, namely BDU, MTZ, TZP, BKI, which increase the dimensions of the protection unit as a whole, reduce the reliability of the starter, and also complicate the maintenance process. The disadvantages also include the lack of an information channel for communication with ACS and memory devices for the formation of an archive of events.

Known explosion-proof magnetic starter PEV-1 (Operation manual TLSK.645317.002RE, DKGSh 31.20.31 Makeevka mine automation plant), made in an explosion-proof housing, containing a disconnector, current sensors, a sensitive element for leakage control, power supplies, indications, remote control, the output of which is connected to the control coil of the contactor, and the remote control is connected to the input.

The disadvantages of the known starter is the lack of indication of controlled parameters, the lack of phase-by-phase voltage monitoring of the three-phase starter network.

Known withdrawable element for complete switchgear switchgear 6-10 kV manufactured by the Power Electrical Equipment Factory "ZSEA" in Cheboksary, where plug-in contacts of the type "Tulip" are used.

The disadvantages of this contact connection are: the complexity of the design and technical manufacture, large dimensions, a small number of contact points.

Known vacuum circuit breaker series VBSK production of JSC "Electrokomplekt" Minusinsk, where plug-in contacts of the type "Tulip" are used.

The disadvantages of this contact connection are: the complexity of the design and technical manufacture, large dimensions, a small number of contact points.

The closest technical solution for the totality of features and the achieved result is an explosion-proof magnetic starter (Pat. RF No. 2436219, IPC H02J 13/00, publ. 2011.12.10), containing a housing in which are located a disconnector, current sensors, a sensitive control element leakage, contactor control coil, power supply, indicating unit, interface with external control systems, remote control unit containing an amplifier, the output of which is connected to the contactor control coil, and the input to the device output asymmetry control, which is connected to an intrinsically safe source of alternating voltage and to a remote control line, at the end of which a control panel is connected, the remote control unit further comprises a phase control device, the output of which is connected to a central control unit, to which a second input and a second output are also connected amplifier, the second input and second output of the asymmetry control device, which provides the block of remote control properties of a protective failure. A three-phase network voltage sensor is installed in the disconnector compartment. A three-phase circuit voltage sensor installed near the contactor power circuits, a temperature sensor, switching element blocks, and devices for interfacing with external dispatch systems can be additionally connected to the central control unit.

The disadvantages of this technical solution are:

- lack of a module that maintains an archive of events;

- a significant complication of the control circuit, due to the introduction of additional feedback from amplifiers, asymmetry control devices and phase control.

The main task solved by the claimed utility model is the creation of an explosion-proof starter that simplifies the design, expands functionality and improves reliability.

The technical result of the utility model is achieved in that an explosion-proof mine starter containing an explosion-proof housing divided into two compartments by an explosion-proof wall, a disconnector-switch is installed in one compartment, which has a modular design with self-cleaning cutting contacts, in another there is a withdrawable unit on which a vacuum contactor, transformer, current and voltage sensors, inductors and other switching elements, two covers adjoin the case, one of which quick-open, two output and one introductory compartments, on the inside of the quick-open lid there is an indication unit and a protection and control unit, characterized in that the protection and control unit is made in the form of a separate module providing the functions of relay protection, automation, control, alarm and equipped with a removable memory module.

The claimed technical result is achieved by the fact that the protection and control module of the starter is based on a microcontroller, which simplifies the design of the protection node, improves the reliability of the starter by eliminating the communication lines between the individual units, and also simplifies the procedure of periodic verification and calibration, as it undergoes diagnostics only only one module. The use of a microcontroller allows you to protect the connection depending on the nature of the load by choosing the type of protective characteristic - normally inverse, very inverse or extremely inverse.

To expand the functionality of the starter, the protection and control module is equipped with a removable memory module for maintaining an archive of events, which allows you to record currents and voltages in phases, power consumption, date and time of receipt of commands for switching on and off, the uptime resource and identify possible causes of failures.

The withdrawable starter assembly is connected to the disconnector using a multi-contact system, which increases the reliability of the contact connection and improves the ease of maintenance of the starter.

The proposed utility model is illustrated by drawings, where in FIG. 1 is a structural diagram of a starter; FIG. 2 is a general view of the disconnector compartment, FIG. 3 is a structural diagram of a withdrawable unit; FIG. 4 shows the construction of a multi-contact connection; FIG. 5 is a general view of the protection and control unit; FIG. 6 - settings panel of the protection and control unit, in FIG. 7 is a functional diagram of a protection and control unit; FIG. 8-10 - characteristics of disconnection of protection against overload of the protection and control unit.

The starter (Fig. 1) consists of a flameproof housing 1 of cylindrical shape, two covers 2 and 3 adjacent to the housing on two sides, one of which 3 is quick opening, inlet 4 and two outlet 5 and 6 (Fig. 2b) squared sections, attached to the body. A withdrawable unit with switching elements and a protection unit are installed inside the housing.

The housing 1 consists of two compartments - the disconnector and the hardware compartment, separated by a flameproof wall 8 (Fig. 1B). In the compartment of the disconnector, on the flameproof wall 8, a disconnector-switch 9 is fixed, which provides both disconnecting the starter from the network and switching the phase rotation for reversing the controlled motor. The axis of rotation of the movable part of the disconnector is brought out of the housing and, using levers located on the side wall of the housing, is connected to the control handle 10 (Fig. 1a). The disconnector-switch is connected to the network using live busbars (not shown in the drawing) and studs 11 on the bushing 12 (Fig. 2a) passing through the wall of the housing into the inlet compartment 4. The disconnector-switch is also connected to the hardware compartment by busbars and studs 13 on bushings 14 (Fig. 1b) passing through the flameproof wall 8. On the side of the disconnector, the starter housing 1 is closed with a blind cover 2, secured with bolts, and on the side of the hardware compartment, with a quick-open cover th 3, suspended from the housing 1 by hinges 15. The quick-open lid 3 is provided with a lock in the form of an expandable spring mechanism mounted on the lid from the side of the hardware compartment. The control of the lock is carried out by the handle 16, displayed on the front side of the cover. The housing 1 is mounted on special rails 17 from a profile pipe.

The introductory compartment is equipped with two cable entries 18 and 19 located on opposite walls and designed to connect power cables.

In the hardware compartment of the starter there is a withdrawable unit 20 assembled on a carriage 21 with rollers 22 moving along the rails 23. The withdrawable unit 20 contains a vacuum contactor 24, a transformer 25, three chokes 26, an electromagnetic contactor 27 (Fig. 3). A block of high-voltage fuses 28 is fixed on the flameproof wall 8 (Fig. 1b).

The withdrawable unit is electrically connected to the disconnector via a detachable multi-contact connection (Fig. 4), which is a pin 29 and a socket 30, between which a spring element 31 is installed, which is a cylinder made of thin material with high electrical conductivity cut along the axis. The cylinder has longitudinal blind slots forming a perforated surface structure that is concave into the cylinder. In a multi-pin connection, the inner concave surface of the cylinder 31 provides a multi-point connection with the pin 29, and the extreme solid elements of the cylinder are in contact with the socket 30. Thus, the spring element provides a multi-point contact between the external surface of the pin and the inner surface of the socket. The pin of each contact connection is the output end of the pin 13 of the bushing 14. The socket 30 of the contact connection is connected to the input buses of the vacuum contactor 24. Current sensors 32 are installed on the sockets 30 of each phase (Fig. 1b). The output of the power circuit of the vacuum contactor using busbars is connected to the studs on the bushings in the lead-out compartment 5. On the side wall of the lead-out compartment 5 there is a cable entry 33 for connecting the load power circuit (Fig. 2b).

The switch-disconnector consists of three contact modules mating together, a locking mechanism, two covers adjacent to the modules, two brackets with tightening pins and a shaft. Each contact module consists of a fixed part - a housing with three self-cleaning cutting contacts made of copper and a moving part - a shaft with a knife-type copper contact poured into it.

Starter control circuits, intrinsically safe circuits and information circuits from the protection unit are led to the terminal compartment 6, to which four cable entries 34 are attached on both sides for connecting control cables. The inlet and outlet compartments of the starter are closed with separate flameproof covers 35 with warning labels on the outer surface.

The starter is equipped with electrical and mechanical interlocks, providing a certain order of interaction of switching equipment. The electrical interlock consists in the fact that to turn the disconnector on or off, it is necessary to press the button 36 (Fig. 3), opening the power supply circuit of the vacuum contactor drive. Mechanical locking consists of a stopper 37, the stroke of the handle of the disconnector 10 and a lever 38 that locks the handle 16 of the quick-open cover 3 (Fig. 1). Before opening the cover 3 of the hardware compartment, it is necessary to disconnect the disconnector by first disconnecting the vacuum contactor by pressing button 36 and unlocking the handle of the disconnector 10 with the travel stop 37. After that, turn the handle 16 counterclockwise by about 180 degrees and pull it towards you.

On the inside of the quick-open lid 3, a protection and control unit (БЗУ) 39 is fixed (Fig. 3), which is a microprocessor device that provides protection functions from various emergency operation modes of the controlled object. An indication unit 40 is electrically connected to the protection unit, in which various emergency situations, to which the protection unit reacts, are coded using light indicators. The display unit is fixed in a special window 41 under the armored glass. Next to the window on the front side of the cover 3 there is a plate 42 with an explanation of emergency codes and a button “Check” 43, designed to control the insulation resistance of the outgoing line before starting the starter.

The protection and control unit 39 is made in the form of a separate module 1 (Fig. 5), which is fixed on the inner side of the quick-open cover 3 of the starter using quick-release clamps.

BZU made on the basis of the microcontroller and is designed to perform the functions of relay protection, automation, control and signaling connections voltage of 660/1140 V.

BZU provides the following types of protection:

- from short circuit currents;

- from overload;

- from complete or partial breakage of one of the phases;

- from spontaneous switching on with a short-term increase in the supply voltage to 150% of the nominal;

- from repeated spontaneous activation upon disappearance and subsequent restoration of voltage;

- from loss of controllability, when the control wires are shorted to each other;

- from an increase in the resistance of the grounding circuit between the starter and the controlled power receiver above the set value (50 Ohms for 1140 V, 100 Ohms for 660 V);

- from switching on the starter when the resistance of the outgoing line decreases below the set value;

- from overheating of the connected motor in the presence of a contact or posistor temperature sensor in it.

Changing the protection settings is carried out by the regulators 2 located on the panel of the protection and control unit. A general view of the settings panel with the purpose of the controls is shown in FIG. 6.

Functional diagram of the protection and control unit (Fig. 7) includes:

- microcontroller;

- current protection unit;

- isolation control unit;

- node for monitoring the resistance of the grounding circuit;

- node for monitoring the resistance of the temperature sensor;

- remote control unit;

- interface with the display unit;

- memory card;

- interface unit with a voltage sensor;

- node relay outputs;

- RS-485 interface node.

The current protection unit performs the functions of protection against short circuits (short circuit) and overloads. Using current protection measuring circuits, phase currents are measured. To convert current in phases to signals for the protection unit, current sensors based on air transformers are used. The integrity of the measuring circuits is checked automatically when the disconnector is turned on and on demand by pressing the "Test" button. In this case, a reference voltage generator with a frequency of 50 Hz is connected to the measuring circuits.

The protection block has three overload tripping characteristics: normally inverse, highly inverse or extremely inverse.

Normal inverse characteristic is applied to engines without inertial load. In this case, the protection is triggered if a long start-up of the electric motor occurs at an unacceptably large load from the side of the driven mechanism.

A strongly inverse characteristic is used to protect against overload of engines with direct start, loaded on inertial mechanisms.

An extremely inverse characteristic is used under severe starting conditions (loaded mechanisms and mechanisms with very high inertia).

The tripping characteristics of the overload protection are shown in FIG. 8-10.

So, for example, knowing the overload coefficient I / I _nom and the time constant set on the CCD, it is possible to determine the response time of the protection using the corresponding characteristic.

The insulation monitoring unit consists of a 100 V voltage source, the short-circuit current of which is limited to 1 mA, and a measuring transducer. The microprocessor unit receives data on the state of isolation, allowing or prohibiting the inclusion of executive relays and the inclusion of the main vacuum contactor. The resistance control of the lighting circuit is performed continuously. The resistance control of the main circuit is performed with the main vacuum contactor switched off. Before turning on the vacuum contactor, the interlock is disconnected from the monitored circuit.

Node for monitoring the resistance of the grounding circuit. Checking the integrity of the grounding wire is carried out by connecting to a controlled circuit an alternating voltage source with a frequency of 133 Hz. At the same time, the gap, the closure of the control wire or the ingress of an extraneous voltage of 50 Hz on it is also controlled. To correctly determine the integrity of the ground wire in the connected equipment, a diode must be installed, located anode to the housing of the starter. This circuit is not galvanically connected to other circuits and is intrinsically safe.

The node for monitoring the resistance of the engine temperature sensor. To protect the motor connected to the starter, the state of the temperature sensor integrated in the motor is monitored. The temperature sensor can be either a contact type (it opens when the permissible temperature is exceeded) or a posistor type (it sharply increases the resistance when the permissible temperature is exceeded). A circuit that monitors the state of the sensor monitors its resistance by measuring the voltage drop under the action of a flowing DC current. The microcontroller unit evaluates the resistance value and, if necessary, disconnects the main vacuum contactor. The circuit has galvanic isolation from other circuits and is intrinsically safe.

The remote control unit is designed to remotely turn the main vacuum contactor on and off by controlling via two wires. An alternating voltage of 133 Hz is supplied to the remote control circuit. A special circuit controls the resistance of the circuit for each half-wave. Depending on the resistance at different half-waves of voltage, the microcontroller unit makes a decision to turn the main vacuum contactor on or off. The circuit of the remote control unit is also intrinsically safe.

The microcontroller performs the logical functions of the protections, provides automatic testing of the circuit when the starter is turned on and the necessary information is transmitted to the display unit and to the process control system, provides internal self-testing and blocking of the inclusion in the event of a malfunction, data archiving using a memory card, measurement of the input voltage of the starter. The settings of the rated current, the multiplicity of the maximum current, blocking resistance, on and off times, etc. are installed before the supply voltage to the protection unit. When the starter is turned on and the voltage is supplied to the BZU, it first of all carries out internal self-testing and reading of the settings. According to the settings, all protections are configured. The readiness of the BZU to turn on occurs no later than 3 seconds after power is supplied.

Protection triggering logging. To maintain a protection operation protocol, a non-volatile memory card is provided, where the time and circumstances of the operation of the protection are stored. If necessary, this data can be read and used to restore the emergency picture.

A connector is provided for connecting a PC or turning it on in an automatic process control system via an RS-485 interface. The RS-485 interface circuit is galvanically isolated from other circuits and is intrinsically safe.

The relay output node, made on the basis of small-sized electromagnetic relays, serves as switching elements in control, protection and interlock circuits.

The interface unit with the voltage sensor is designed to measure the voltage of the starter supply circuit.

The use of a modern microprocessor element base in the device provides high measurement accuracy and constant characteristics, which can significantly increase the sensitivity and speed of protection.

The proposed utility model allows you to create an explosion-proof mine starter with advanced functionality and high reliability.

Claims (3)

1. Explosion-proof mine starter containing a flameproof enclosure, divided into two compartments with an explosion-proof wall, a switch-disconnector is installed in one compartment, a withdrawable unit is installed on the other, on which a vacuum contactor, transformer, current and voltage sensors, chokes and other switching elements are installed, two outlets and one inlet compartment adjoin the case, two covers, one of which is quick-open, on the inside of which there is an indication unit and a protection unit and control detecting, comprising an interface with external systems, scheduling, characterized in that the protection and control unit is a separate module and a removable memory module. 2. Explosion-proof mine starter according to claim 1, characterized in that the protection and control module provides protection of the connection against overload depending on the nature of the load by selecting the type of protective characteristic - normally inverse, very inverse or extremely inverse. 3. Explosion-proof mine starter according to claim 1, characterized in that the withdrawable unit is connected to the disconnector using a multi-contact system.

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