SU1654912A1 - Device for protecting electric drives of sucker-rod pumps against emergency conditions - Google Patents

Abstract

The invention relates to electrical engineering, in particular, to a protection protection. The purpose of the invention is to increase the sensitivity and reliability of protection. In overload mode, a current exceeding the rated current flows in the secondary winding of the current transformer 7 and the winding of the ammeter 8, the contact of the arrow 9 of the ammeter 8 is closed with the limit contact of the ammeter 12, the thyristor 11 is opened, the first relay 14 is activated, and the contact 28 is closed in the coil circuit of the second relay 21 which, with time delay, closes its contact 30, opens contacts 31, 32. If the contact closure time of the arrow is 9 ami (L

Description

The invention relates to electrical engineering, in particular, to relay protection, and can be used to protect the electric drive of a subtrain pump from emergency operation.

The purpose of the invention is to increase the sensitivity and reliability of protection,

The diagram shows the functional scheme of the device for protecting the electric drive of a submersible pump from emergency operation.

The device for protection of the electric Irivod in the form of a three-phase electric motor 1 of a sucker-rod pump from emergency mode contains a magnetic starter, the power contacts 2 of which are tfH connected to the supply mains and the second to the phase outputs of the three-phase electric motor 15 the start 3 button are bridged block, to the contact 4 of the magnetic starter and connected by the first terminal to the terminal for connection to one phase conductor of the network, and the other terminal through the Stop button 5 - 4 by the first terminal of the winding 6 of the magnetic starter, transformer Ator 7 toiЈa, the primary winding of which is designed to be connected in series into one of the phase conductors supplying a three-phase electric motor 1, contact ammeter 8, connected to the secondary winding of the current transformer 7, while the mobile contact 9 connected with the arrow of the tact-ampermeter 8, connected through the first resistor 10 to the control electrode of the thyristor 11, the anode of which is connected to the limiting con- tacts 12 of the contact ammeter 8 and to the positive terminal of the first rectifying bridge 139 minus terminal otorrhea through the winding 14 of the first relay connected to the first terminal of the second resistor 15, four capacitors, the first 16 and second 17 capacitors are interconnected in series and the first capacitor 16 to its first terminal CO-,

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connected to a terminal for connecting a three-phase electric motor 19 to a single phase output and a second capacitor 17 to its terminals connected to the input terminals of the first rectifying bridge 13, a second rectifying bridge 20 connected by its input leads to the terminals of the third capacitor 18 the second capacitor 17 and the common point of its output and the input output of the second rectifying bridge 20 is connected to a terminal for connection with another phase output of a three-phase electric motor, four The capacitor 19 is connected by its terminals to the positive and negative terminals of the first rectifying bridge, the windings of the second 21 and third 22 relays are bounded by the fifth 23 and sixth 24 capacitors, respectively, and the winding of the third relay 22 is also bridged sequentially interconnected first closing contact 25 of the second relay 21 and the third resistor 26, with the first winding terminals of the second 21 and third 22 relays being combined and connected to the first output terminal of the second rectifying bridge 20, The second winding terminal of the second relay 21 through the first variable resistor 27 is connected to the first terminal of the second closing contact 28 of the second relay 21, the second winding terminal of the third relay 22 via the second variable resistor 29 is connected to the first terminal of the closing contact 30 of the first relay 14, second terminals of the mentioned closing contacts 28 and 30 of the second 21 and first relay 14 are combined and connected to the second output terminal of the second rectifying bridge 20; the second terminal of the second resistor is connected to the cathode via the first break contact 31 of the second relay 21 m thyristor 11, a second normally closed contact 32 of the second relay 21, the contact switch zashun- tirovenny

33 and the disconnecting contact 34 of the third relay 22, with one output connected to the second terminal of the winding of the magnetic actuator 6, and the other BEING home to the terminal for connection to the second phase conductor of the network.

The security device operates as follows.

Pressing the Start button 3 turns on the magnetic starter. At the output of the current transformer 7 and the flow through the ammeter 8 current flows 5-6 times higher than the nominal. At the same time, the arrow of the ammeter 8 is closed with the limit contact 12 located on the right side of the scale, the circuit of the control electrode of the thyristor 11. The thyristor 11 is opened and the first relay 14 is activated, closes its closing contact 28 in the circuit of the second relay 21 ", Relay 23 turns on The shutter speed of the starting current of the electric motor 1 is activated. The closing contact 30 is turned on in the winding circuit of the third relay 22 and the contacts 31 and 32 open on the cathode of the thyristor 11 and the magnetic starter. The thyristor 11 is turned off, respectively, the first relay 14 is turned off, opening its contact 28 in the circuit of the second relay 21 Relay 21 is turned off. Since the constant response time of relay 22 is longer than the constant response time of relay 21, the third relay 22 does not operate, and its opening contact 34 in the magnetic starter circuit does not turn off in the start mode, which also provides a detuning of the protection from the starting current. After the expiration time of the inrush current, the thyristor 11 is locked, the ammeter shows the operating current of the three-phase electric motor 1 of the electric drive. In stationary mode, the arrow of the ammeter 8 indicates the operating current, the thyristor 11 is locked, the relays 14, 21 and 22 are off, the contacts 32 and 34 are closed, the switch 33 is open (it is closed only when the protection setting is calibrated).

In the overload mode in all phases of the network, the current increases and becomes higher than the allowable. Accordingly, on the secondary winding of the current transformer 7 and in the winding of the ammeter 8 prote

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Forces a current exceeding the rated voltage. At the same time, the contact of the arrow of the ammeter 8 is closed with the organic contact 12 located on the right side of the scale, according to the protection setting, the circuit of the control electrode of the thyristor 11, the latter opens, the first relay 14 is activated, the circuit is closed 28 in the second relay circuit 21. Relay 21 is turned on with time delay, contact 30 of the second relay 21 is closed, and contacts 32 and 31 are opened.

- If the needle of the ammeter remains closed with a limiting contact, the thyristor is unlocked again. During the switching time of the thyristor 11, the relay 21 remains switched on, since the capacitor 23 does not have time to discharge. The relay 22 triggers, opening its contact 34. The magnetic starter 24 is de-energized and the three-phase motor 1 is disconnected from the network.

In idle mode (decrease in load), the load current in all phases decreases to the value of the idling current of the electric motor 1, at the output of the current transformer 7 and in the winding of the ammeter 8 - below the permissible value. At the same time, the contact of the arrow of the ammeter 8 is closed with the limiting contact 12 located on the left side of the scale, according to the protection setting, short circuit: the control electrode circuit of the thyristor 11. The thyristor 4 is unlocked and the protection operates the same as in the overload mode.

When a phase break occurs, both on the low side and on the high side, or if the voltage is not allowed to unbalance, the current flowing through the winding of the ammeter 8 increases. In this case, the protection device operates similarly to the overload mode of the three-phase electric motor 1 of the electric drive.

When a phase break occurs, in the circuit of which current transformer 7 is connected, the current through the ammeter 8 winding decreases below the permissible value. At this point, the device operates in the same way as the idle mode.

Thus, the advantage of the proposed device in comparison with the prototype is the high efficiency and reliability of electrical protection.

drive from emergency modes, as well as high sensitivity protection.

Claims (1)

Invention Formula A device for protecting an electric sucker rod pump from emergency operation, containing a magnetic starter, the power contacts of which are designed to be connected to the power supply terminal and the second to the phase output MIJT of the three-phase electric motor, connected to the start button. terminal with a terminal for connection with one phase network wire 0m, and the other terminal through the Stop button - with the first terminal of the magnetic starter winding, the current transducer Ko V0poro winding intended for inclusions. Permanently into one of the phase circuits, powered by a three-phase electric motor, a contact ammeter, connected to the secondary winding of the current transducer, while the first connected to the arrow of the contact ammeter is connected to the secondary winding of the current transformer. a resistor with a thyristor control electrode, the contact contacts of the contact ammeter are connected to the thyristor anode and to the positive terminal of the first rectifying bridge, the negative terminal of which through the winding of the first relay is connected to the first terminal of the second resistor, four cond The first and second capacitors are connected to each other in series and the first capacitor is connected to the terminal for connecting the three-phase electric motor to one phase output, and the second capacitor is connected to the input terminals of the first rectifier bridge, T l and h It’s so that with the aim of 50 To increase reliability and sensitivity of protection, it additionally provides Compiler V. Orlov Editor A “Shandor Tehred M. Dtsdyk 0 five 0 five 0 five 0 five 0 ov but the fifth and sixth capacitors, the third resistor, the first and second variable resistors, the switch, the second and third relays, the second rectifying bridge connected by its input pins to the pins of the third capacitor, which is connected to the serial circuit of the second capacitor and the input terminal of the second rectifying bridge, connected to the terminal for connection with another phase output of the three-phase electric motor, the fourth capacitor is connected by its leads to the positive and minus The main terminals of the first rectifying bridge, the windings of the second and third relays are shunted respectively by the fifth, sixth capacitors, while the windings of the third relay are also shunted by a chain consisting of the second relay and the third resistor in series with the third contact, and the first windings the second and third relays are combined and connected to the first output terminal of the second –switching bridge; the second terminal of the winding of the second relay is connected to the first output terminal via the first variable resistor The second relay winding terminal is connected to the first terminal of the first relay, the second terminals of the second and first relay contacts are connected and connected to the second output terminal of the second rectifier bridge, the second terminal of the second resistor the first break contact of the second relay is connected to the thyristor cathode, the second break contact of the second relay, grounded by the switch contact and the break contact one relay, one output connected to the second output winding of the magnetic starter, and the other output - with a terminal for connecting to the second phase conductor of the network. Proofreader S. Shekmar