SU1295471A1 - Current filter-relay - Google Patents

Abstract

The invention relates to the field of automation of energy systems and can be used in relay protection and anti-fault automation. The aim of the invention is to expand the scope and increase sensitivity. The goal is achieved by introducing a two-level comparing device 7 into the current filter relay, a first input connected to the output of the adder 6, a second input to the setting unit 9, and an output to the input of the reacting element 8, the output of which is the output filter of the current relay, connected through the RETURN DELAY 12 element to the input of the setting unit 9, as well as to the control circuits of the key 5. In the initial state, the setting setpoint for the operation is connected to the input of the comparison device 7 by setting setting 9 after switching off damage- of the set point again switches to the indicated one. The magnitudes of the setpoint voltages are chosen based on the highest load current surge and the motor load self-starting current after the elimination of the damage. 1 з.п, ф-л, 3 Il. (L to co. Sd (rig

Description

The invention relates to the automation of energy systems and can be used in relay isolation and emergency control.

The aim of the invention is to expand the field of application and increase the sensitivity of the filter-current relay.

Pa Fig, 1 presents a diagram of the proposed device; in fig. 2 is an example of a specific implementation of the device; in fig. 3 - timing charts of the device.

The current filter-relay contains an input current converter 1 (for example, a current transformer), installed on a protected transmission line 2, a controlled signal shaper 3, an input element connected to the input converter tj, a 5-key, a key 5, an adder 6, a two-level comparison device 7, Control element 8, block 9 for setting parameters 5 including source 10 of reference directions and switch 1 1 and RETURN DELAY element 12.

The device works as follows.

The voltage from the output of the imager 3 of the monitored signal is fed to the input of the delay element 4 and to the first input of the adder 6. The key 5 is closed in the normal state. The delay element 4, made on the basis of a fourth order phase filter, has a phase delay at a frequency of 50 Hz equal to 10 ms, and an amplitude transmission coefficient equal to one. In the steady state at the output of the adder 6, and therefore, at the first input of the two-level comparator device 7, the voltage is zero. To the second input of the two-level comparator device 7 from the setpoint setting unit 9, a constant setpoint voltage is applied to the operation and. determined by the maximum possible load surge on the protected line 2 and formed on the first output of the source 10 reference voltages. Blocks 7 and 8 are in this mode. They are in their original unset state.

In the event of a short circuit in the press section of the line (Fig. 3), the outputs of the comparators of the two-level comparing device 7 (one of the comparators controls the amplitude of the positive half-waves, the other - negative)

the pulses, if the voltage value at the output of the adder 6 exceeds the setpoint of the reacting element 8, triggers, sends a voltage to disconnecting the line switch with its output signal, opens the key 5, and switches the switch 11 and the setpoint from the voltage and, , on Ui ,,. The latter is formed in the source 10 of reference voltages on the basis of the maximum self-starting current of the motor load after disconnecting the damaged section and its subsequent switching on. The delay time for the return of item 12 is selected by the formula

 to "(h" in + t ,.

),

20

with

,

-

thirty

0

five

0

where is the automatic reclosing time (AR) of the line; ,

tjj is the delay time of element 4; K - reliability factor

(To „1).

After disconnecting the protected area (Fig. 2, t), the pulses at the output of the two-level comparing device 7 disappear, but the reacting element 8, which, according to its principle of operation, has a delay of. return, returns to its original state after 0.01 s, due to which a transition from the transients in the delay element 4 is performed. Key 5 closes. After the operation of the AR device (Fig. 2), after a time t of 0.01 s (necessary for detuning the two-level comparing device 7 from a voltage jump at the output of the adder as a result of ARF), the setpoint in the reference voltage source 10 is switched to the initial U , The circuit returns to the original condition (Fig. 2, t.

Thus, the introduction of a two-level comparison device, a key, a setpoint setting block, a RETURN DELAY element and an adder allows to increase the sensitivity of the current filter-relay by detuning from the value of the monitored signal in the pre-emergency mode.

The proposed device can be used as a device for overcurrent protection with the EXTRA function required (: rG, ttani and return.

312

Claims (2)

1. Current filter-relay containing an input current transducer included in the corresponding phase of the protected line, a delay element, a reacting element and a controlled signal shaper, the inputs of which are connected to the output of the current transducer, so that, in order to expand the scope of application by performing the functions of the overcurrent relay and increasing the sensitivity, a two-level comparison unit, a key, a setting unit, a RETURN DELAY element and the adder, while the two-level comparison block is connected to the input of the reacting element by the output, the first input to the output of the setting unit, the second input to the output of the adder, its first input connected to you 714 to the input of the delayed element and to the input of the delay element, the second input to the output of the key, information input connected to the output of the delay element, the control input to the output of the response element, to the input of the RETURN DELAY element whose output is connected to the control input of the task unit the settings, and the input of the DELAY TO RETURN item is connected to the circuit breaker tripping circuits. 2. Filter relay according to claim 1, which is based on the fact that the setpoint setting block is made up of a source of reference voltages and a switch, while the source of the reference voltages is connected to the corresponding inputs of the switch The control input of which is the control input of the setpoint setting block, and the output is the output of the setpoint block. L Compiled by K. Shilan Editor I.Nikolaychuk Tehred V.Kadar Order 624/59. Circulation 619 Subscription VNIIZh USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 ag.Z Proofreader V. Booth ha