RU159857U1 - RELAY PROTECTION DEVICE IN 6-10 kV POWER NETWORK - Google Patents

Abstract

The relay protection device in the 6-10 kV power network, consisting of a current transformer with a measuring organ winding connected to it on the magnetic circuit, which also has inductive sensors of current cut-off (MOT) and maximum current protection (MTZ), are connected in cascade to each sensor, respectively a rectifier, amplifier and comparator, and the outputs of the comparators are connected, respectively, to the first, second input of the microcontroller, characterized in that the microcontroller is supplemented with the first and second analog-to-digital converter (ADC), moreover, the first one is connected through the low-pass filter to the output of the TO pulse amplifier, and the second one is connected to the MTZ setpoint timer, and the first output of the microcontroller is connected via its driver to the control input of the first triac, which unloads the 6-10 kV circuit breaker coil and the second microcontroller output is connected , respectively, through its driver to the control input of the second triac connected in series with the aforementioned 6-10 kV circuit breaker coil, which in turn is connected to the aforementioned mu current transformer, and the settings of MOT and MTZ are set on the provided setpoints at the inputs, respectively, of the amplifier MOT and MTZ.

Description

The utility model relates to the field of electrical engineering, in particular to the section of relay protection.

It is known [1] induction relay of maximum current with dependent and independent time delay RT-85 close to the target. It has a number of disadvantages, such as bulky dimensions and low reliability due to moving mechanical parts.

Known [2] relay protection devices using microprocessor technology of similar design. It also has disadvantages, in particular, the impossibility of using the energy of the accident to trip the 6-10 kV circuit breaker.

The purpose of the utility model is to increase reliability by eliminating moving mechanical parts and reducing the dimensions of the device and using the energy of the accident to trip the 6-10 kV circuit breaker.

The goal is achieved in that the relay protection device in the 6-10 kV power network, consisting of a current transformer with a measuring organ winding connected to it on a magnetic circuit, which also has inductive sensors of current cut-off (MOT) and overcurrent protection (MTZ), A rectifier, amplifier and comparator are cascaded to each sensor, respectively, and the comparator outputs are connected respectively to the first, second input of the microcontroller, while the microcontroller is supplemented by the first and second analog-to-digital converters by the driver (ADC), the first connected via a low-pass filter to the output of the TO pulse amplifier, and the second connected to the MTZ setpoint timer, and the first output of the microcontroller connected via its driver to the control input of the first triac, unloading the 6-10 kV circuit breaker , and the second output of the microcontroller is connected respectively through its driver to the control input of the second triac connected in series with the aforementioned 6-10 kV circuit breaker coil, which in turn is connected and to the aforementioned current transformer, and the settings of TO and MTZ are set on the provided setpoints at the inputs of the TO amplifier and MTZ, respectively.

The figure 1 shows a functional block diagram containing:

1 - current transformer of controlled power load of 6-10 kV;

2 - winding of the magnetic circuit of the measuring body;

3 - magnetic circuit of the measuring body;

4 - triac normally open;

5 - triac normally closed;

6 - electromagnet tripping the switch 6-10 kV;

7 - overcurrent protection sensor;

8 - current cutoff sensor;

9 - rectifiers;

10 - setpoint switch for overcurrent protection;

11 - setpoint switch current cutoff;

12 - differential pulse amplifier of overcurrent protection;

13 - differential amplifier pulse current cutoff;

14 - comparators;

15 - microcontroller;

16 - triac driver;

17 - setpoint temporary settings of the maximum current protection;

18 - low pass filter.

Principle of operation:

The signals from the sensors 7, 8 are fed to the rectifiers 9, as a result of which the negative half-waves of the signals are cut off, then the reference signals 10, 11, which set the maximum current protection and current cut-off settings, respectively, are subtracted from these pulses using differential amplifiers 12, 13, and also output the signals are amplified using the same differential amplifiers 12, 13. Next, the output signals with the help of comparators 14 are converted into rectangular pulses and fed to the input of the microcontroller 15.

To control the magnitude of the current with the subsequent implementation of the dependence of the response speed on the magnitude of the flowing current of the protected circuit from the output of the differential amplifier 12, the pulses are fed to a low-pass filter 18, where they are smoothed, and the finished signal is fed to the input of the analog-to-digital converter of the microcontroller 15.

To set the time delay of the overcurrent protection, a time setpoint 17 is used, the signal from which is fed to the second input of the analog-to-digital converter of the microcontroller 15.

From the output of the microcontroller 15, signals are sent to the driver 16, which control the operation of the triacs 4, 5.

When one of the protections is triggered, the electromagnet 6 trips the 6-10 kV circuit breaker; the triac 5 first opens, then the triac 4 with some delay.

Information taken into account:

1.http: //rele35.narod.ru/RT_85.html

2.http: //www.abb.com/product/db0003db004281/30caa87e80f65a02c1257458003dfa42.aspx

Claims (1)

The relay protection device in the 6-10 kV power network, consisting of a current transformer with a measuring organ winding connected to it on the magnetic circuit, which also has inductive sensors of current cut-off (MOT) and maximum current protection (MTZ), are connected in cascade to each sensor, respectively a rectifier, amplifier and comparator, and the outputs of the comparators are connected, respectively, to the first, second input of the microcontroller, characterized in that the microcontroller is supplemented by the first and second analog-to-digital converter (ADC), moreover, the first one is connected through the low-pass filter to the output of the TO pulse amplifier, and the second one is connected to the MTZ setpoint timer, and the first output of the microcontroller is connected via its driver to the control input of the first triac, which unloads the 6-10 kV circuit breaker coil, and the second microcontroller output is connected , respectively, through its driver to the control input of the second triac connected in series with the aforementioned 6-10 kV circuit breaker coil, which in turn is connected to the aforementioned mu current transformer, and the settings of MOT and MTZ are set on the provided setpoints at the inputs, respectively, of the amplifier MOT and MTZ.

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