CN107993540A - A kind of microcomputer protective relay teaching experiment system - Google Patents

Abstract

The present invention designs an experimental system applied to the teaching of microcomputer relay protection, including a digital operation module 1, an electric power collection and control module 2 and a data interaction module 3, wherein the digital operation module 1 is connected with the electric power collection and control module respectively. Module 2 and the data interaction module 3 are connected; in the digital operation module 1, the operation models of different relay protection types are constructed, and according to the data of the power collection and control module 2, through the data interaction module 3 Manual or automatic setting to form an experimental system of different relay protection types to realize fault judgment and control, and record relevant operating information. The invention can integrate various microcomputer relay protection modes into a unified experiment platform, and can carry out various microcomputer relay protection experiments, thereby improving the training effect of electric system relay protection operators.

Description

A microcomputer relay protection teaching experiment system

technical field

The invention relates to the field of electric system teaching experiment devices, in particular to a microcomputer relay protection teaching experiment system.

Background technique

The teaching process of microcomputer relay protection technology mainly includes various fault characteristics and their manifestations in physical quantities such as electricity, and the practice and testing of parameter setting methods. In the experimental teaching, the microcomputer relay protection device used in the power system is directly used as the teaching instrument. Due to the diversity and difference of the relay protection types in the teaching, a variety of microcomputer protection devices are required, which is not conducive to the development of teaching activities. The experimental teaching is only used for the microcomputer relay protection device, and cannot fully present the learning process of the microcomputer relay protection technology. For relay protection learners, there is no corresponding detailed introduction to the principles of the process, which increases the difficulty of learning.

Microcomputer relay protection requires high operating speed and calculation accuracy. Generally, different special equipment is used for different protection types, which is expensive. Using the microcomputer relay protection device running in the actual project for teaching, there are problems of waste of resources and various types, and the existing microcomputer relay protection experiment device is not compatible with different types of relay protection methods, generally the focus is on In terms of the verification of experimental parameters, it is impossible to fully present the key points and difficulties in the process of learning and practicing microcomputer relay protection technology, which is not conducive to the development of experimental teaching.

Therefore, it is necessary to study a microcomputer relay protection teaching technology, which can develop a variety of typical relay protection experiments on a single experimental device, so as to improve the learning effect of relay protection technology for the practical teaching of relay protection technicians .

Contents of the invention

The purpose of the present invention is to overcome the above existing technical problems and provide an idea compatible with common power system relay protection types of hardware and software modules to build a microcomputer relay protection experiment system.

In order to achieve the above purpose, the present invention designs an experimental system applied to the teaching of microcomputer relay protection, including a digital operation module 1, an electric power acquisition and control module 2 and a data interaction module 3, wherein the digital operation module 1 and the The power collection and control module 2 and the data interaction module 3 are connected; in the digital operation module 1, different types of relay protection operation models are constructed, and according to the data of the power collection and control module 2, through the The manual or automatic setting of the data interaction module 3 forms an experimental system of different relay protection types to realize fault judgment and control, and records relevant operating information.

Wherein, the power collection and control module 2 includes an analog quantity measurement module 21, a switch quantity measurement module 22 and a switch quantity output module 23, all of which are independent module units, and can be combined according to the type of relay protection.

Wherein, the relay protection operation model built in the digital operation module 1 can be selected through the manual or automatic setting mode of the data interaction module 3, and carry out specific data and hardware resource configuration according to the above selection; data configuration Mainly set various factors in the relay protection setting method in the operation model; the hardware resource configuration is mainly for the selected relay protection type and its operation model to configure the analog measurement module 21, the switch measurement module 22 and the switch The specific channel of the volume output module 23.

Wherein, the design of the relay protection calculation model built in the digital operation module 1 adopts a flow design scheme; the flow design scheme sets up a plurality of different flow simulation basic control programs in the operation process of different relay protection types and abnormal handling during operation. Each process contains several steps, which are used to simulate the specific operation steps of the relay protection detection and control program or fault handling. Each process includes the jump step number, the maximum operation time, and the condition set and relay action sets.

Among them, the process is divided into simple operation process and multi-step program operation process.

Wherein, the simple operation flow is used for fault handling during the operation of the microcomputer relay protection, and only the operation condition set is detected in the step, and if the predetermined condition is met, the predetermined relay action is executed, and if not satisfied, the step is exited.

Among them, in the multi-step program operation process, starting from the first step, the set of detection conditions is periodically cyclically detected within the maximum operating time. If the predetermined conditions are met, the predetermined relay action will be executed and the next step will be executed. If not, the cycle will continue until When the maximum operation time is exhausted, if the condition set is still not satisfied, exit the loop and enter the new step pointed to by the jump step number to continue execution.

Among them, the relay protection calculation model designed based on the simple operation process includes single-phase low-voltage protection, specifically including:

1. Collect all AC electrical quantities and obtain sampling data of each AC electrical quantity;

2. Select a phase A line voltage sampling data;

3. Calculate the amplitude according to the sampling data of a phase A line voltage;

4. Select the low-voltage protection module, that is, judge that the voltage of a phase A line is lower than the threshold, judge that a fault has occurred and go to step 5, otherwise return to step 1;

5. Output the relay control signal according to the relay action set.

Wherein, the relay protection calculation model designed based on the multi-step program operation flow includes three-phase line overcurrent protection, specifically including:

1. Collect all AC electrical quantities and obtain sampling data of each AC electrical quantity;

2. Select a three-phase line current sampling data;

3. Calculate the amplitude according to the current sampling data of a three-phase line;

4. Select the module of overcurrent section I, II, and III to judge the amplitude of a certain three-phase line current and the threshold value of overcurrent section I, II, and III. The action setting values are in descending order, if If the amplitude is higher than the threshold of the overcurrent section I, it is judged that a fault has occurred and it is transferred to step 5; if the amplitude is between the thresholds of the overcurrent section I and II, start the first timing T1 until the timing ends, and it is judged that a fault has occurred And turn to step 5; if the amplitude is between the thresholds of overcurrent section II and section III, start the second timing T2 until the end of the timing, judge that a fault has occurred and turn to step 5; if the above condition sets are not satisfied , then turn to step 1 for loop detection until the maximum operating time is exhausted, then exit the three-phase line overcurrent protection.

5. Output the relay control signal according to the relay action set.

Wherein, the switch value output module 23 includes a relay control circuit, and the relay control circuit includes a DC power supply, a main switch tube S2, a first switch tube S1, a discharge switch tube S3, a charging resistor R, a bidirectional DC/DC converter, a storage Energy capacitors C1 and C2 and the control unit, the DC power supply output terminal is connected to the DC bus, the energy storage capacitor C1 is connected in parallel to the positive and negative poles of the DC bus, and the main switch S2 is connected in series on the DC bus to control the input of electric energy on the DC bus. The first switching tube S1 is connected in series with the charging resistor R to form the first charging branch, the first charging branch is connected in parallel with the main switching tube S2, one end of the bidirectional DC/DC converter is connected to the energy storage capacitor C2, and the other end is connected in parallel with the DC bus, the switch The tube S3 is used to control the output of electric energy on the DC bus; when the power is turned on for the first time, the first switch tube S1 in the first charging branch is closed, and part of the electric energy of the DC power supply is charged to the energy storage capacitor C1, and the other part is passed through the bidirectional DC/DC The converter charges the energy storage capacitor C2, and when the voltage of the energy storage capacitor C2 rises to the first set value, the control unit controls the bidirectional DC/DC converter to stop charging the energy storage capacitor C2, and transfers the voltage in the energy storage capacitor C2 to The electric energy is released to charge the energy storage capacitor C1 on the DC bus. When the voltage of the energy storage capacitor C1 on the high-voltage DC reaches a steady state and the voltages on both sides of the main switch are equal, the main switch S2 is closed, and the main switch S2 is closed. Afterwards, the first switching tube S1 is disconnected, and the first power-on ends.

The beneficial effect of implementing the invention is that various microcomputer relay protection modes can be integrated into a unified experiment platform, and various microcomputer relay protection experiments can be carried out, thereby improving the training effect of power system relay protection operators.

Description of drawings

Fig. 1 is a structural block diagram of the present invention.

Figure 2 is a flowchart of a simple operation process.

Figure 3 is a flow chart of the operation flow of the multi-step program.

Fig. 4 is a schematic diagram of the relay control circuit of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, it can be seen that the system includes a digital operation module 1, a power collection and control module 2 and a data interaction module 3. The digital operation module 1 is connected with the power acquisition and control module 2 and the data interaction module 3 .

Wherein, the operation models of different relay protection types (overcurrent protection, low voltage protection, distance protection, differential protection, etc.) are constructed in the digital operation module 1, and according to the data of the power collection and control module 2, Through the manual or automatic setting of the data interaction module 3, different typical relay protection modes are realized to realize fault judgment and control, and relevant operation information is recorded.

The power acquisition and control module 2 includes an analog quantity measurement module 21, a switch quantity measurement module 22 and a switch quantity output module 23, all of which are independent module units. The analog quantity measurement module 21, the switch quantity measurement module 22 and the switch quantity output module 23 can all be combined according to the type of relay protection.

The analog measurement module 21 can collect DC and AC analog quantities, the DC analog quantity interface includes a common power access mode for 0-5V voltage and 0-20mA current, and the AC analog quantity interface includes a rated voltage of 100V transformer AC voltage and Rated current 60A transformer AC current access method.

The relay protection operation model built in the digital operation module 1 can be selected through manual or automatic setting of the data interaction module 3, and specific data and hardware resource configurations can be performed according to the above selection. The data configuration is mainly for setting various factors in the relay protection setting method in the operation model; the hardware resource configuration is mainly for the selected relay protection type and its operation model to configure the analog measurement module 21 and the switch measurement module 22 And the specific channel of the switch value output module 23 forms a complete relay protection experiment platform.

The design of the relay protection operation model built in the digital operation module 1 adopts the concept of process design. The scheme does not specifically define the meanings of various data collected in the power collection and control module 2, and the specific definitions and calculations are all completed through the parameter settings in the process design scheme. The process design plan sets up several processes to simulate the basic control procedures and abnormal handling during operation of different relay protection types. Each process contains several steps for simulating the detection and control procedures of relay protection or fault handling. The specific operation steps, each process includes the jump step number, the maximum operation time, condition set and relay action set. The process is divided into simple operation process and multi-step program operation process. As shown in Figure 2, the simple operation flow can be completed with only one step. This is used for fault handling during the operation of the microcomputer relay protection. There is no connection between the steps of this flow, and only the set of operating conditions is detected in the step. If the predetermined condition, execute the predetermined relay action, and exit the step if it is not satisfied. In this case, the maximum operating time is meaningless; the other is a multi-step program operation process, as shown in Figure 3, which requires multiple steps to complete. After confirming the process number Finally, starting from the first step, the set of detection conditions is regularly cycled within the maximum operating time. If the predetermined conditions are met, the predetermined relay action will be executed and the next step will be entered. If not, the cycle will continue until the maximum operating time is exhausted. If the condition set is still not satisfied, exit the loop and enter the new step pointed to by the jump step number to continue execution. The process design plan incorporates the basic control program of the microcomputer relay protection and the fault handling of the operation, which is more holistic.

According to the general situation of microcomputer relay protection, the flow design scheme can set the number of total flow and the number of steps of each flow, and each step includes jump step number, condition set and relay action set. The condition set includes the hardware resources of the analog measurement module 21 and the switch measurement module 22 , and the relay action set includes the hardware resources of the switch output module 23 .

For example: single-phase (such as a phase A line) low-voltage protection adopts simple operations, and the specific steps are as follows:

1. Collect all AC electrical quantities and obtain sampling data of each AC electrical quantity;

2. Select a phase A line voltage sampling data;

3. Calculate the amplitude according to the sampling data of a phase A line voltage;

4. Select the low-voltage protection module, that is, judge that the voltage of a phase A line is lower than the threshold, judge that a fault has occurred and go to step 5, otherwise return to step 1;

5. Output the relay control signal according to the relay action set.

Another example: the three-phase line overcurrent protection adopts a multi-step operation process, and the specific steps are as follows:

1. Collect all AC electrical quantities and obtain sampling data of each AC electrical quantity;

2. Select a three-phase line current sampling data;

3. Calculate the amplitude according to the current sampling data of a three-phase line;

4. Select the module of overcurrent section I, II, and III, that is, to judge the amplitude of a certain three-phase line current and the threshold value of overcurrent section I, II, and III (action setting values in order from large to small), if If the amplitude is higher than the threshold of the overcurrent section I, it is judged that a fault has occurred and it is transferred to step 5; if the amplitude is between the thresholds of the overcurrent section I and II, start the first timing T1 until the timing ends, and it is judged that a fault has occurred And turn to step 5; if the amplitude is between the thresholds of overcurrent section II and section III, start the second timing T2 until the end of the timing, judge that a fault has occurred and turn to step 5; if the above condition sets are not satisfied , then turn to step 1 for loop detection until the maximum operating time is exhausted, then exit the three-phase line overcurrent protection.

5. Output the relay control signal according to the relay action set.

In the prior art, the relay coil needs to be driven by a large current to generate action. If the high current is provided directly through the power supply, the power supply will be bulky and inefficient. Therefore, the energy storage capacitor is generally charged by the power supply, and then discharged through the energy storage capacitor. Generate a large current to drive the relay coil. The specific circuit includes a DC power supply, a main switch tube S2, a DC bus, an energy storage capacitor C1, and a discharge switch tube S3. The output end of the DC power supply is connected to the input end of the DC bus bar, and the energy storage capacitor C1 is connected in parallel. Between the positive and negative poles of the DC bus, it is used to store the electric energy output by the DC power supply. The main switching tube S2 is connected in series with the DC bus to control the input of electric energy on the DC bus. The discharge switch S3 is used to control the electric energy on the DC bus. output.

The specific control process is as follows: when the power is turned on for the first time, the main switch tube S2 is closed, and the DC power supply charges the energy storage capacitor through the DC bus. After charging, the output voltage of the DC power supply is equal to the voltage at both ends of the energy storage capacitor. When the discharge switch tube S3 is closed, The energy storage capacitor discharges, because the energy storage capacitor has a large capacitance, so the discharge current is very large. However, when the power is turned on for the first time, due to the existence of capacitance, if the main switch S2 is directly closed, there will be a large voltage difference between the DC power supply side and the DC bus side when it is closed, and the main switch S2 will flow through the pole. A large current may easily cause damage to the main switch tube S2, and at the same time affect the life of the energy storage capacitor.

In order to solve the above problems, the present invention provides a relay control circuit that can effectively reduce the large current generated when the main switch S2 is turned on for the first time. As shown in Figure 4, the relay control circuit includes a DC power supply, a main switch tube S2, a first switch tube S1, a discharge switch tube S3, a charging resistor R, a bidirectional DC/DC converter, energy storage capacitors C1 and C2, and a control unit (not shown in the figure), the output terminal of the DC power supply is connected to the DC bus, the energy storage capacitor C1 is connected in parallel to the positive and negative poles of the DC bus, the main switching tube S2 is connected in series on the DC bus, and the first switching tube S1 is connected in series with the charging resistor R to form the second A charging branch, the first charging branch is connected in parallel with the main switch tube S2, one end of the bidirectional DC/DC converter is connected to the energy storage capacitor C2, and the other end is connected in parallel to the DC bus, and is used to convert the electric energy of the energy storage capacitor C2 to the Charge the energy storage capacitor C1, or charge the energy storage capacitor C2 after converting the electric energy on the DC bus, the discharge switch tube S3 is used to control the output of electric energy on the DC bus, and the control unit is used to collect the output voltage of the DC power supply, energy storage The voltage of the capacitor C2 and the DC bus voltage (that is, the voltage of the energy storage capacitor C1 ) control the charge and discharge of the energy storage capacitor C2 during the first power-on and normal operation.

The working process is as follows: when the power is turned on for the first time, the first switch tube S1 in the first charging branch is closed, part of the electric energy of the DC power supply is charged to the energy storage capacitor C1, and the other part is charged to the energy storage capacitor C2 through the bidirectional DC/DC converter , when the voltage of the energy storage capacitor C2 rises to the first set value, the control unit controls the bidirectional DC/DC converter to stop charging the energy storage capacitor C2, and discharges the electric energy in the energy storage capacitor C2 to the storage on the DC bus The energy storage capacitor C1 is charged. When the voltage of the energy storage capacitor C1 reaches a steady state and the voltages on both sides of the main switch S2 are equal, the main switch S2 is closed, and the first switch S1 is turned off after the main switch S2 is closed. Electricity is over. During the first power-on process, due to the current limiting effect of the discharge resistor R, the charging current can be effectively reduced, and the energy of the energy storage capacitor C2 is released to the energy storage capacitor C1 through the bidirectional DC/DC converter, so that the DC The voltage on the bus side is almost equal to the voltage on the DC power supply side, that is, the voltage difference is almost zero, which further reduces the large current generated when the main switch S2 is closed.

During normal operation, the main switch tube S2 remains closed, and the control unit controls the bidirectional DC/DC converter to charge the energy storage capacitor C2 again. When the voltage of the energy storage capacitor C2 rises to the second set value, the energy storage capacitor C2 After the charging is completed, the bidirectional DC/DC converter is on standby, and the second set value is greater than the first set value; when the DC power supply is normal and the discharge switch S3 is closed, the control unit controls the DC power supply and the energy storage capacitor C1 to supply the relay together. The coil supplies power, drives the relay to act, and completes the switching action; when the DC power supply fails and the discharge switch S3 is closed, the control unit controls the bidirectional DC/DC converter to release the electric energy in the energy storage capacitor C2, and together with the energy storage capacitor C1, the relay The coil supplies power to drive the relay to act. At this time, the energy storage capacitor C2 acts as a backup power supply, so as to ensure the completion of the action of the relay in the event of a DC power failure, and improve the reliability of the action of the relay.

The above-given embodiments are used to illustrate the present invention and its practical effects, and are not intended to limit the present invention in any form. Any person skilled in the art can make a decision based on the above techniques and methods within the scope of the technical solutions of the present invention. Certain modifications and alterations should be considered as equivalent embodiments with equivalent alterations.

Claims (10)

1. a kind of microcomputer protective relay teaching experiment system, it is characterised in that including digital operation module 1, electric quantity acquisition and control Molding block 2 and data interaction module 3, wherein the digital operation module 1 respectively with the electric quantity acquisition and control module 2, institute Data interaction module 3 is stated to connect；The operational model of the different relay protection types of structure, root in the digital operation module 1 According to the electric quantity acquisition and the data of control module 2, by the manually or automatically setting of the data interaction module 3, formed not Experimental system with relay protection type realizes breakdown judge and control, and records related operation information.

2. microcomputer protective relay teaching experiment system according to claim 1, it is characterised in that the electric quantity acquisition and control Molding block 2 includes analog measurement module 21, switch measurement module 22 and switching value output module 23 and forms, and is independent Modular unit, and can be combined according to relay protection type selector channel.

3. microcomputer protective relay teaching experiment system according to claim 2, it is characterised in that the digital operation mould The relay protection operational model of structure, can be selected by the manually or automatically set-up mode of the data interaction module 3 in block 1 Select, and specific data and hardware resource configuration are carried out according to above-mentioned selection；Data configuration is mainly for relay in operational model All kinds of factors in protection seting method are configured；Hardware resource configures the relay protection type and its fortune mainly for selection Calculate the specific logical of the model configuration analog measurement module 21, switch measurement module 22 and switching value output module 23 Road.

4. microcomputer protective relay teaching experiment system according to claim 3, it is characterised in that the digital operation mould In block 1 process design plan is used in the design of the relay protection operational model of structure；The process design plan is provided with more Primary control program (PCP) and running abnormality processing in a different flowsheeting difference relay protection type operational process, often A flow includes several steps, for simulating the concrete operation step of relay protection Detection ＆ Controling program or troubleshooting, Each flow includes jump procedure number, operation maximum time, condition set and actuating of relay collection.

5. microcomputer protective relay teaching experiment system according to claim 4, it is characterised in that flow is divided into simple operations Flow and multi-step process operating process.

6. microcomputer protective relay teaching experiment system according to claim 5, it is characterised in that the simple operations flow For the troubleshooting in microcomputer protective relay operational process, operating condition collection is detected in step, if meeting established condition, Perform the set actuating of relay.

7. microcomputer protective relay teaching experiment system according to claim 5, it is characterised in that multi-step process operation stream Cheng Zhong, since first step, the timing cycle detection condition set within operation maximum time, if meeting established condition, holds The set actuating of relay of row simultaneously enters next step, if not satisfied, continuing cycling through when exhausting operation maximum time, if condition Collection is still unsatisfactory for, and the circulation is exited, into the next step.

8. microcomputer protective relay teaching experiment system according to claim 6, it is characterised in that based on the simple operations The relay protection operational model of flow scheme design includes single-phase under-voltage protection, specifically includes：

1. all AC electric quantities of collection, obtain the sampled data of each AC electric quantity；

2. select certain A phase line voltage sample data；

3. calculate amplitude according to certain A phase line voltage samples data；

4. selecting under-voltage protection module, that is, judge that certain A phase lines voltage is less than threshold value, be judged as breaking down and be transferred to the 5th Step, otherwise returns to the 1st step；

5. according to actuating of relay collection output relay control signal.

9. microcomputer protective relay teaching experiment system according to claim 7, it is characterised in that based on the multi-step journey The relay protection operational model of sequence operating process design includes three-phase line overcurrent protection, specifically includes：

1. all AC electric quantities of collection, obtain the sampled data of each AC electric quantity；

2. the selection three-phase line current sampling data；

3. amplitude is calculated according to the three-phase line current sampling data；

4. selecting I sections of overcurrent, II sections, III root modules, that is, judge the amplitude and I sections of overcurrent, II of certain three-phase line electric current Section, III sections of threshold value, wherein the threshold value successively from big to small, if amplitude is higher than I sections of threshold values of overcurrent, is judged as occurring Failure is simultaneously transferred to the 5th step；If amplitude between I sections and II sections threshold values of overcurrent, starts the first timing T1 until timing knot Beam, amplitude still are judged as breaking down and are transferred to the 5th step between I sections and II sections threshold values of overcurrent；If amplitude is between mistake Between II sections and III sections threshold values of electric current, start the second timing T2 until timing terminates, amplitude is still between II sections of overcurrent and III It is judged as breaking down between section threshold value and is transferred to the 5th step, wherein the second timing T2 is more than the first timing T1；If above-mentioned condition Collection is unsatisfactory for, then is transferred to the circulation of the 1st step and is detected, until operation maximum time exhausts, exit the three-phase line overcurrent Protection.

5. according to actuating of relay collection output relay control signal.

10. according to claim 1-9 any one of them microcomputer protective relay teaching experiment systems, it is characterised in that switching value Output module 23 includes control relay circuit, and the control relay circuit includes DC power supply, main switch S2, first Switching tube S1, discharge switch pipe S3, charging resistor R, two-way DC/DC converters, storage capacitor C1 and C2 and control unit, directly Galvanic electricity source output terminal is connected with dc bus, and storage capacitor C1 is parallel to dc bus positive and negative anodes, and master is in series with dc bus Switching tube S2, for controlling the input of direct current bus bar energy, first switch pipe S1 connects to form the first charging with charging resistor R Branch, the first charging paths are in parallel with main switch S2, and two-way DC/DC converters one end connects storage capacitor C2, the other end with Dc bus is in parallel, and switching tube S3 is used for the output for controlling direct current bus bar energy；When powering on first, the first charging paths are closed In first switch pipe S1, DC power supply electric energy a part to storage capacitor C1 charge, another part by two-way DC/DC change Parallel operation charges to storage capacitor C2, and when the voltage of storage capacitor C2 rises to the first setting value, control unit controls two-way DC/ DC converters stop charging to storage capacitor C2, and the electric energy in storage capacitor C2 is released to the storage capacitor on dc bus C1 charges, when the storage capacitor C1 voltages in high voltage direct current reach stable state, and main switch both sides voltage it is equal when Main switch S2 is closed, first switch pipe S1 is disconnected after main switch S2 closures, powers on end first.