SU792459A2 - Device for differential protection of transformer with regulating voltage under load - Google Patents

Description

lei, the adder acting on the multiplying device, one input of the specified adder is connected with the output of the integrator adder, and the second one is connected to the displacement circuit, which specifies the unit transfer coefficient of the multiplying device.

The disadvantages of such a device are insufficient speed in case of internal damage to the transformer, accompanied by significant currents, due to delays caused by the tuning blocks from the surge of magnetizing current and braking, lowering the sensitivity and selectivity of protection due to accumulation from the control circuit. transfer coefficient multiplier in a closed circuit in the idle code (XX) power transformer, since the adder is input a-integrator applied, a voltage proportional to the current XX of the transformer, a balanced voltage, proportional to the load current of the transformer, no regardless of its actual position.

The aim of the invention is to increase the speed, sensitivity and selectivity of the differential protection of a power transformer with voltage regulation under load.

The goal is achieved by the fact that the device for differential protection of a transformer with voltage regulation under load is additionally equipped with a key and a cutoff unit, one of the inputs of which is connected to the output of the operating signal shaper, and the rest to the inputs of the latter, the output of the cutoff unit is connected to one of the inputs the switch of the output unit, and the key is connected between the output of the integrator and its feedback resistor, with the key control circuit connected to the output of the module driver.

The drawing shows a protection scheme in which a number of elements are shown in a block image, and a part in principle. The object of protection is a multi-winding transformer 1, in which the adjustable winding is indicated by an arrow. The outputs of the transformer 1 in a single-line image show current transformers (T T) 2, 3, 4 connected by secondary windings to current transformers 5, 6, 7.

The outputs of the inverters current voltage 5,6,7 are connected to the inputs of the operating signal generator (FRS) 8j of the braking signal generator (FTS) 9, the unit for comparing g of the working and braking signal (BSRC) 10, and the output of the converter 5 fed from T T 2 adjustable winding of the transformer 1, is connected to the inputs of these blocks

Q through a multiplying device 11, and the outputs of the other converters 6 7 Directly. A positive signal from the FRS unit 8, a brake signal from the output of the FCS 9 and a voltage setting are also fed to the input of the SBRTS unit. To one of the inputs of the block of the FCS 9 is connected to the output of negative half-waves of the block FRS 8.

To the output of the variable signal block FRS (8) is connected to the block tune

0 from the magnetizing current surge (VO), in which 1-a and 2-harmonics are separated by band-pass filters,. their modules are formed and fed to output block (XB) 12, to

5 to the input of which the output of the SBRTS unit (10) is also connected and the setting voltage is applied.

The change in the transmission coefficient of the multiplying device 11 is carried out by the block BIN (13), which consists of a voltage adder, proportional to the load currents 14, the inputs of which are connected to the outputs of the converters 6, 7, the former

5 to 15, connected at the output of adder 14, shaper module 16, connected via switch 17 to converter 5 (open-loop regulation) or to the output of multiplying device 11 (closed-loop control), integrator with output signal limitation 18, to the inputs which are oppositely supplied from the drivers of modules 15 and 16 and the output

5 is connected to the input of the adder 19. A bias voltage corresponding to one (1) of the transmission coefficient of the multiplying device 11 controlled from the adder 19 is applied to the second input of the adder 19.

Claims (1)

 The cut-off block 20, introduced to improve speed at high internal short-circuit currents, consists of an adder 21, at one of the inputs of which a positive half-wave voltage is fed from the output of the fed 8 and the rest voltage, proportional to the currents of the protection arms, the comparator 22 and voltage source settings. The transfer coefficient of the adder 21 at the first input is taken twice as large as the rest, so that a voltage proportional to the differential current module is formed at its output. The output of the cut-off unit 20 is connected to one of the inputs of the dedunctor 23 of the output unit 12. The second additionally introduced block The key 24 is connected between the output of the integrator 18 and its feedback resistor 25. The key is closed in the absence of a control signal supplied from the driver of the MODULE 15. Due to this, the integration of a voltage proportional to the current X X of the transformer 1 coming from the spinner 15 and the drift voltage of the operational amplifier of the integrator 18 when controlled in a closed circuit in the X X mode of the transformer is prevented. When the load current of the transformer 1 appears, the key 24 is disconnected and the transfer coefficient of the multiplying device 11 is set to the corresponding equilibrium voltage of the NII received at the input of the integrator 18. In the diagram, the switch 17 is shown in the position corresponding to the closed control circuit. It should be noted here that the closed regulation scheme is basic, since it, being essentially an astatic controller, is characterized by the absence of a static error and does not place high demands on the linearity of the multiplying device 11. Based on the foregoing, it can be concluded that as a result of In the scheme of the device of new elements and connections, the effect of increasing the speed, sensitivity and selectivity of the device has been obtained. DETAILED DESCRIPTION OF THE INVENTION A device for differential protection of a transformer with voltage regulation under load according to the author. 649085, characterized by the fact that, in order to increase speed, sensitivity and selectivity, it is additionally equipped with a key and a cutoff unit, one of the inputs of which is connected to the output of the operating signal shaper, and the rest to the inputs of the latter, the output of the cutoff unit is connected to one of the inputs the disjunctor of the output block, the key is connected between the output of the integrator and its feedback resistor, with the key control circuit connected to the output of the module driver. ; - "ff in j: -.- . Th i. : i. l f. .-lu.- L, ftj