RU2109302C1 - Device for checking of n alternating currents - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: device has N current transformers 1.1...1N, primary 2.1...2N and secondary 3.1...3N windings of current transformers, first and second capacitors 4, 5, stabilizer diode 5, relay 7, rectifying diodes 8, transistors 9.1...9N-1, and diodes 10.1...1ON-1. EFFECT: reduced number of connections with current transformers positioned in close proximity to power object construction. 1 dwg

Description

 The invention relates to monitoring devices, in particular linear AC circuits, for example, for signaling damage to lines and can be used as a signal for interference in complex systems consisting of several power lines.

 Known devices for monitoring alternating currents, containing measuring current transformers loaded on ammeters [1]. Such devices carry out the transformation of alternating current, electrical isolation of signals and measurement of current magnitude. The disadvantage of such devices is the low reliability in harsh operating conditions and the absence of signaling devices that promptly and visually show the loss of current or its unacceptable decrease.

 Also known are devices for monitoring alternating currents, in which noncontact measuring devices are used as the controlling body, which make it possible to realize almost any alarm function and have high reliability under all operating conditions [2]. The disadvantage of these devices is the complexity and high cost.

 Closest to the proposed one is an AC current monitoring device containing current transformers, along the primary windings of which alternating currents flow, and the secondary windings of the transformers through rectifiers are connected to pulse shapers consisting of transistors, as well as I, OR elements and an actuator [3].

 The disadvantage of such devices is the high complexity and cost when it is necessary to control several power circuits and currents flowing through them. Moreover, for each control relay, a separate connection is necessary, which leads to a significant increase in the cost of control systems.

 The technical result is to reduce the number of connections from current transformers installed in the immediate vicinity of the controlled power facility to the point with a control relay.

 The specified technical result is achieved by the fact that in the device for monitoring N currents (or N lines) one pair of wires is used. Signaling to disable the monitoring relay on this circuit is carried out by switching sequentially connected (N-1) transistors controlled from the secondary windings (N-1) of the current transformers. In this case, the voltage realizing the attracted state of the control relay is provided by the secondary winding of the 1st current transformer. The device does not require a separate power source.

 The drawing shows an electrical diagram of a control device for N alternating currents.

 The control device for alternating currents contains N current transformers 1.1, 1.2 ... 1.N primary windings N current transformers 2.1 ... 2.N secondary windings N current transformers 3.1 ... 3.N first capacitor 4, zener diode 5, second capacitor 6, relay 7, rectifier diodes 8, transistors 9.1 ... 9.N-1, diodes 10.1 ... 10.N-1.

 The control device N variable currents works as follows.

 In the presence of alternating currents flowing along the primary windings 2.1 ... 2. N-1 current transformers 1.1 ... 1.N, currents will also flow in their secondary windings 3.1 ... 3.N, thanks to which the transistors 9.1 ... 9.N-1 will be open during one half-periods of the alternating current, and during other half-periods these transistors will be closed, the continuity of the currents of the secondary windings is ensured by the diodes 10.1 ... 10. (N-1).

 Secondary current circuit 3.1. current transformer 2.1. closes on relay 7 through open transistors 9.1 ... 9.N-1 and diodes 8.

 If the current disappears in the primary winding 2.1 of the current transformer 1.1, then the current disappears in the secondary winding 3.1, which leads to the release of relay 7 and the inclusion of its corresponding signaling through its contacts.

 If the current disappears in one of the primary windings 2.2 ... 2.N-1, then this leads to the disappearance of current in the corresponding secondary windings 3.2 ... 3.N and to the blocking of one of the transistors 9.1 ... 9.N-1 . This causes the release of relay 7. In this case, to protect the locked transistors from excess voltage at the output of the rectifier diodes 8, a zener diode 5 is installed.

Claims (1)

 A control device for N alternating currents, where N ≥ 2, containing N current transformers, N controlled alternating currents flow through the perimeter windings of the current transformer, and the secondary winding of the first current transformer is connected through a half-wave rectifier to the first and second terminals of the first capacitor, the first terminal of which is connected to the first relay output, characterized in that a second capacitor, a zener diode, N - 1 transistors, N - 1 diodes are introduced into it, where the second output of the first capacitor is connected to the collector of the first transistor, and e the ytter of the (N - 1) -th transistor to the second relay terminal and the first terminal of the second capacitor, the second terminal of which is connected to the first relay terminal, and the collector-emitter junctions of the transistors are connected in series so that the emitters of the previous transistors - starting from the 1st on the (N - 2) th are connected to the collectors of subsequent transistors - starting from the 2nd to the (N - 1) th, respectively, and each of the secondary windings of the current transformers, starting from the 2nd to the Nth, is shunted by a diode, starting from the 1st through the (N - 1) th, and connected to the base and emitter of each of t anzistorov with 2 to (N - 1) th, respectively, and parallel to the first capacitor included zener diode.