CN108539754A - Intelligent Capacitive switching combination switch and switching control method - Google Patents

Abstract

An intelligent capacitor switching composite switch and switching control method, which can realize the state monitoring and fault diagnosis, switching control of three independent composite switches, and realize zero-crossing detection of voltage, local human-computer interaction and communication with Controller wireless communication function. It is composed of an intelligent composite switch control board and a composite switch. The intelligent composite switch control board includes a micro-control unit, an on-site human-computer interaction unit connected to the micro-control unit, a voltage zero-crossing detection unit, a state monitoring and fault diagnosis unit, The switching control unit and the communication unit, the composite switch is connected with the switching control unit, and the single composite switch is composed of a bidirectional thyristor SSR and an AC contactor normally open contact KM connected in parallel, and the thyristor realizes voltage zero-crossing input and current zero-crossing removal, The continuous current is passed through the normally open contact of the AC contactor, which avoids the conduction loss problem of the thyristor and also avoids the inrush current when the capacitor is switched on.

Description

Intelligent Capacitor Switching Composite Switch and Switching Control Method

technical field

The invention relates to a capacitor switching device and a switching method, in particular to a power system reactive power compensation intelligent capacitor switching composite switch and a switching control method.

Background technique

Reactive power compensation is a technology that reduces the loss of power supply transformers and transmission lines, improves power supply efficiency, and improves the power supply environment. It plays a role in improving the power factor of the power grid in the power supply system. The reactive power compensation device based on the capacitor bank plays an indispensable and very important position in the power supply system. The static compensation method of delay switching is a common switching method of capacitors, which can prevent the capacitor from being damaged by too frequent actions, and more importantly, prevent the power supply system from oscillating due to the continuous switching of capacitors. The corresponding devices for controlling capacitor switching mainly include AC contactors, thyristors, compound switches and synchronous switches.

Capacitor switching compound switch has two types: common compensation switch and separate compensation switch. The common compensation switch is used for switching three-phase capacitors and adopts △ connection method; the division compensation switch is used for switching single-phase capacitors and adopts Y-shaped connection method. The composite switch uses a thyristor switch and a magnetic latching switch to operate in conjunction. It has the characteristics of a thyristor zero-crossing switching at the moment of turning on and off, and has the characteristics of zero power consumption of a magnetic latching switch during normal turn-on. The composite switch has the advantages of no impact, low power consumption, long life, etc. It can replace contactors or thyristor switches, and is widely used in the field of low-voltage reactive power compensation. The traditional compound switching switch realizes the monitoring from the controller to the compound switch by hard wiring, and the way of common compensation and sub-compensation is selected by dialing the key switch, which has the disadvantages of complicated operation, inconvenient use, and poor versatility. Adapt to the development needs of modern information technology.

Contents of the invention

Aiming at the problems existing in the traditional composite switching switch, the present invention takes the microprocessor as the core, provides an intelligent capacitor switching composite switch and a switching control method, and realizes the status monitoring, fault diagnosis and switching of three independent composite switches. It realizes zero-crossing detection of voltage, local human-computer interaction and wireless communication with the controller.

The intelligent capacitor switching composite switch involved in the present invention is composed of an intelligent composite switch control board and a composite switch. Zero-crossing detection unit, state monitoring and fault diagnosis unit, switching control unit and communication unit, the composite switch is connected with the switching control unit; a single group of composite switch is composed of bidirectional thyristor SSR and AC contactor normally open contact KM connected in parallel, contact The on-off of the coil KM is controlled by the control circuit of the AC contactor. The voltage zero-crossing input and current zero-crossing cut-off are realized by the thyristor, and the continuous current is passed through the normally open contact of the AC contactor, thus avoiding the conduction loss of the thyristor. It also avoids the inrush current when the capacitor is switched on.

Further preferably, the micro-control unit includes a central processing unit, a JATG interface connected to the central processing unit and a memory, and the central processing unit communicates with the outside world through a data line, a communication line, an interactive interface and a control line; The interactive unit includes manual switching switch and configuration touch screen, the voltage zero-crossing monitoring unit includes voltage and current transformers and AD analog-to-digital converters, the status monitoring and fault diagnosis unit includes power quality monitoring chips and fault status indicators, and the switching control unit Including the isolator, the overall switching control terminal and the split-phase switching control terminal, the composite switch is connected to the overall switching control terminal and the split-phase switching control terminal, and the communication unit includes WIFI communication module, RS232 communication module, Zigbee communication module and Ethernet communication module; the data line is connected with the voltage and current transformer, the power quality monitoring chip, the JATG interface and the memory, and respectively realizes the real-time monitoring of the voltage and current signal, power quality information monitoring, program debugging and data storage functions; the communication line and the WIFI The communication module, RS232 communication module, Zigbee communication module and Ethernet communication module are connected to realize the wired/wireless remote control function of various communication modes; the interactive interface is connected to the manual switching switch, configuration touch screen and fault status indicator light to realize On-site manual control, touch screen human-computer interaction, fault status indicator light control, through the touch screen to observe and display compensated power quality parameters including reactive power, grid voltage, current, and frequency; the control line is connected to the isolator to realize three Control of an independent composite switch and realize signal isolation.

Further preferably, the entrances of the intelligent capacitor switching composite switch are respectively connected to live wires L1, L2, L3 and the neutral line N, and the outlets of the intelligent capacitor switching composite switch are connected to integral switching capacitors or split-phase switching capacitors; The capacitor bank is used for reactive power compensation, and only the outlet terminals A, B, and C are used for wiring. When the phase-separated switching capacitor bank is used for reactive power compensation, terminals A, B, C, and N are used for wiring.

Further preferably, the AD analog-to-digital converter is integrated in the central processing unit.

The switching method of the intelligent capacitor switching composite switch is as follows:

1. The intelligent capacitor switching compound switch accepts the manual switching switch input command and the remote input command of the communication unit;

1.1 The micro control unit first judges whether there is a remote input command through the communication unit, if yes, enters the link of detecting the grid voltage by the voltage transformer; if not, then judges whether there is a manual input command through the local human-computer interaction unit, if yes, Then enter the link of detecting the grid voltage; if not, return to the judgment of the remote input command;

1.2 After entering the grid voltage detection link, judge whether the grid voltage has crossed zero, if yes, enter the thyristor trigger conduction link; if not, return to the grid voltage detection link;

1.3 After entering the thyristor trigger conduction link, delay 20-50ms, and then enter the link of judging whether the thyristor is conducting; judge whether the thyristor is conducting through the current transformer of the state detection unit and the power quality monitoring chip, and if so, enter the contactor control Coil energization link; if not, enter the thyristor open circuit fault alarm and display link, and then end the operation;

1.4 After entering the energization link of the contactor control coil, delay 1-2s, the thyristor triggers off, and enters the link of whether the normally open contact of the contactor is closed;

1.5 Determine whether the normally open contact of the contactor is closed, if so, end the operation; if not, the contactor control coil is powered off, the contactor cannot absorb the fault alarm and indication, and then end the operation.

2. The intelligent composite switch accepts the cut-out command of the manual switching switch and the remote cut-out command of the communication unit;

2.1 First judge whether there is a remote cut-out command through the communication unit, if yes, enter the thyristor trigger conduction link; if not, judge whether there is a manual cut-out command through the local human-computer interaction unit, if yes, start the thyristor trigger conduction link; if not, return to the judgment of the remote switching command;

2.2 After entering the thyristor trigger conduction link, after a delay of 20-50ms, the contactor coil is powered off, after a delay of 1-2s, the thyristor is triggered off, the thyristor current is zero-crossing and cut off, and then enters the judgment of whether the normally open contact of the contactor is disconnected links

2.3 Use the current transformer of the state detection unit and the power quality monitoring chip to judge whether the normally open contact of the contactor is disconnected, if yes, end the operation; if not, the contactor armature does not release the fault alarm and indication, and then end the operation.

Further preferably, the input command of the manual switching switch has priority.

Compared with the traditional capacitor switching switch, it has the following beneficial effects:

The system has Ethernet communication, RS232 communication, WIFI communication and Zigbee communication functions, which can meet various user needs and facilitate communication with other intelligent terminals. Abandon the previous hard-wiring method between reactive power compensation control and switching switch, which brings great convenience to system installation and maintenance.

The system realizes local manual switching control, and can also accept remote control commands sent by reactive power compensation control. Manual switching control is convenient for users to debug on site, and remote switching control realizes the automatic control function of reactive power compensation.

The system integrates status monitoring and fault diagnosis functions. The status detection function can observe and display the power quality parameters such as reactive power compensation, grid voltage, current, frequency and so on in real time. When the system is put into and cut out, the system adds fault diagnosis functions such as contactor not sucking in, contactor armature not releasing, thyristor open circuit, etc., effectively ensuring the safe and reliable operation of the system.

Description of drawings

Fig. 1 is an overall functional block diagram of the present invention;

Fig. 2 is the functional block diagram of the circuit of the intelligent composite switch control board;

Fig. 3 is a schematic diagram of an intelligent composite switching switch system;

Figure 4 is a schematic diagram of the wiring of the overall switching capacitor bank/separate phase switching capacitor bank;

Fig. 5 is a schematic diagram of a single group composite switch;

Fig. 6 is a composite switch input control flow chart;

Fig. 7 is a flow chart of the composite switch cut-out control.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments, and the specific embodiments are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

The invention uses a microprocessor as the core to realize the state monitoring, fault diagnosis and switching control of three independent composite switches, as well as the zero-crossing detection of the voltage, local human-computer interaction and wireless communication with the controller. The overall functional block diagram is shown in Figure 1. The intelligent capacitor switching composite switch is composed of an intelligent composite switch control board and a composite switch. The intelligent composite switch control panel includes a micro-control unit, an on-site human-computer interaction unit connected to the micro-control unit, a voltage zero-crossing detection unit, a state monitoring and fault diagnosis unit, a switching control unit and a communication unit, and a switching Combination switch for control unit connection.

Described intelligent composite switch control board, as shown in Figure 2, micro-control unit is made of central processing unit adopting DSPF28335, JATG interface and memory, communicates with the outside world through data line, communication line, interactive interface and control line. The on-site human-computer interaction unit includes a manual switching switch and a configuration touch screen, and the voltage zero-crossing monitoring unit includes a voltage current transformer and an AD analog-to-digital converter. In this embodiment, the AD analog-to-digital converter is integrated in the central processing unit, and the state The monitoring unit and fault diagnosis unit include a power quality monitoring chip (ATT7022 chip) and a fault status indicator light. The switching control unit includes an isolator, an overall switching control terminal and a separate phase switching control terminal, a composite switch and an overall switching control terminal. It is connected with the split-phase switching control terminal, and the communication unit includes a WIFI communication module, an RS232 communication module, a Zigbee communication module and an Ethernet communication module. The data line is connected with the voltage and current sensor, the power quality chip, the JATG interface and the memory, and realizes the real-time monitoring of the voltage and current signal, power quality information monitoring, program debugging and data storage functions respectively. The communication line is connected with the WIFI communication module, RS232 communication module, Zigbee communication module and Ethernet communication module to realize the wired/wireless remote control function of various communication modes. The interactive interface is connected with the manual switching switch, the configuration touch screen, and the fault status indicator to realize local manual control, touch screen human-computer interaction, and fault status indicator control respectively. The control line is connected with the isolator to realize the control of three independent composite switches and realize signal isolation.

As shown in Figure 3, the entrance of the intelligent capacitor switching composite switch is connected to L1, L2, L3 live wire and N neutral wire respectively, and the outlet is connected to the overall switching capacitor or the split phase switching capacitor. As shown in Figure 4, if the integral switching capacitor bank is used for reactive power compensation, only the terminals A, B, and C of the outlet are used for wiring; , N terminal.

The composite switch of a single group is shown in Figure 5. The composite switch of a single group is composed of a bidirectional thyristor SSR and an AC contactor normally open contact KM in parallel. The contactor coil KM is energized or de-energized by the AC contactor control circuit. Realize voltage zero-crossing input and current zero-crossing cut-off, and the AC contactor normally open contact KM passes continuous current, thus avoiding the conduction loss problem of the thyristor SSR, and also avoiding the inrush current when the capacitor is switched on.

The switching method is as follows:

1. As shown in Figure 6, the input process of the intelligent capacitor switching composite switch:

1.1 The micro control unit first judges whether there is a remote input command through the communication unit, if yes, enters the link of detecting the grid voltage by the voltage sensor; if not, then judges whether there is a manual input command through the local human-computer interaction unit, if yes, then Enter the link of detecting grid voltage; if not, return to the judgment of remote input command;

1.2 After entering the grid voltage detection link, judge whether the grid voltage has crossed zero, if yes, enter the thyristor trigger conduction link; if not, return to the grid voltage detection link;

1.3 After entering the thyristor triggering conduction link, delay 40ms, enter the judgment whether the thyristor is conducting or not. Through the current transformer of the state detection unit and the power quality monitoring chip to judge whether the thyristor is on, if yes, enter the link of electrification of the contactor control coil; if not, enter the link of thyristor open circuit fault alarm and display, and then end the operation;

1.4 After entering the power-on link of the contactor control coil, delay for 2s, the thyristor triggers off, and enters the link of whether the normally open contact of the contactor is closed;

1.5 Determine whether the normally open contact of the contactor is closed, if so, end the operation; if not, the contactor control coil is powered off, the contactor cannot absorb the fault alarm and indication, and then end the operation.

2. As shown in Figure 7, the switching process of the intelligent capacitor switching composite switch:

2.1 First judge whether there is a remote cut-out command through the communication unit, if yes, enter the thyristor trigger conduction link; if not, judge whether there is a manual cut-out command through the local human-computer interaction unit, if yes, start the thyristor trigger conduction link; if not, return to the judgment of the remote switching command;

2.2 After entering the thyristor trigger conduction link, after a delay of 40ms, the contactor coil is powered off, and after a delay of 1s, the thyristor is triggered to turn off, the thyristor current is cut off at zero crossing, and then enters the link of judging whether the normally open contact of the contactor is disconnected;

2.3 Use the current transformer of the state detection unit and the power quality monitoring chip to judge whether the normally open contact of the contactor is disconnected, if yes, end the operation; if not, the contactor armature does not release the fault alarm and indication, and then end the operation.

Claims (6)

1. An intelligent capacitor switching composite switch is characterized in that: it is composed of an intelligent composite switch control panel and a composite switch, and the intelligent composite switch control panel includes a micro-control unit, an on-site man-machine connected with the micro-control unit respectively Interaction unit, voltage zero-crossing detection unit, state monitoring and fault diagnosis unit, switching control unit and communication unit, the composite switch is connected with the switching control unit; a single group of composite switches consists of a bidirectional thyristor SSR and an AC contactor normally open contact KM Composed in parallel, the on-off of the contactor coil KM is controlled by the control circuit of the AC contactor, the voltage zero-crossing input and the current zero-crossing are realized by the thyristor, and the continuous current is passed through the normally open contact of the AC contactor, thus avoiding the conduction of the thyristor The problem of pass loss also avoids the inrush current when the capacitor is switched on. 2. The intelligent capacitor switching compound switch according to claim 1, characterized in that: the micro-control unit includes a central processing unit, a JATG interface and a memory connected to the central processing unit, and the central processing unit is connected to the central processing unit through a data line , communication line, interactive interface and control line to communicate with the outside world; the local human-computer interaction unit includes manual switching switch and configuration touch screen, the voltage zero-crossing monitoring unit includes voltage and current transformers and AD analog-to-digital converters, status monitoring and The fault diagnosis unit includes a power quality monitoring chip and a fault status indicator light. The switching control unit includes an isolator, an overall switching control terminal and a separate phase switching control terminal. The composite switch is connected to the overall switching control terminal and the separate phase switching control terminal. The communication unit includes a WIFI communication module, an RS232 communication module, a Zigbee communication module and an Ethernet communication module; the data line is connected to a voltage and current transformer, a power quality monitoring chip, a JATG interface and a memory, respectively realizing real-time monitoring of voltage and current signals, Power quality information monitoring, program debugging and data storage functions; the communication line is connected with the WIFI communication module, RS232 communication module, Zigbee communication module and Ethernet communication module to realize the wired/wireless remote control function of multiple communication modes; interactive interface Connect with manual switching switch, configuration touch screen, and fault status indicator to realize local manual control, touch screen human-computer interaction, and fault status indicator control respectively. Observation and display compensation through the touch screen include reactive power, grid voltage, and current 1. Power quality parameters of frequency; the control line is connected to the isolator to realize the control of three independent composite switches and realize the isolation of signals. 3. The intelligent capacitor switching composite switch according to claim 1, characterized in that: the entrances of the intelligent capacitor switching composite switch are respectively connected to live wires L1, L2, L3 and neutral line N, and the intelligent capacitor switching The outlet of the composite switch is connected to the integral switching capacitor or the split-phase switching capacitor; when the integral switching capacitor bank is used for reactive power compensation, only the outlet terminals A, B, and C are used for wiring; when the split-phase switching capacitor bank is used for reactive power compensation , Terminals A, B, C, N are used for wiring. 4. The intelligent capacitive switching composite switch according to claim 1, characterized in that: the AD analog-to-digital converter is integrated in the central processing unit. 5. Adopt the switching method of the intelligent capacitance switching compound switch as claimed in claim 1, it is characterized in that: the steps are as follows: 1) The intelligent capacitor switching composite switch accepts the input command of the manual switching switch and the remote input command of the communication unit; 1.1) The micro control unit first judges whether there is a remote input command through the communication unit, if yes, enters the link of detecting the grid voltage by the voltage transformer; if not, then judges whether there is a manual input command through the local human-computer interaction unit, if yes , then enter the link of detecting the grid voltage; if not, return to the judgment of the remote input command; 1.2) After entering the grid voltage detection link, judge whether the grid voltage has crossed zero, if yes, enter the thyristor trigger conduction link; if not, return to the grid voltage detection link; 1.3) After entering the thyristor trigger conduction link, delay 20-50ms, and then enter the link of judging whether the thyristor is conducting; judge whether the thyristor is conducting through the current transformer of the state detection unit and the power quality monitoring chip, and if so, enter the contactor Control coil energization link; if not, enter the thyristor open circuit fault alarm and display link, and then end the operation; 1.4) After entering the energization link of the contactor control coil, delay 1-2s, the thyristor triggers off, and enters the link of whether the normally open contact of the contactor is closed; 1.5) Determine whether the normally open contact of the contactor is closed, if yes, end the operation; if not, the contactor control coil is powered off, the contactor cannot absorb the fault alarm and indication, and then end the operation. 2) The intelligent composite switch accepts the cut-out command of the manual switching switch and the remote cut-out command of the communication unit; 2.1) First judge whether there is a remote cut-out command through the communication unit, if yes, enter the thyristor trigger conduction link; if not, judge whether there is a manual cut-out command through the local human-computer interaction unit, if yes, perform thyristor Trigger the conduction link; if not, return to the judgment of the remote switching command; 2.2) After entering the thyristor trigger conduction link, after a delay of 20-50ms, the contactor coil is powered off, and after a delay of 1-2s, the thyristor is triggered off, the thyristor current is zero-crossing and cut off, and then enters whether the normally open contact of the contactor is disconnected Judgment link; 2.3) Use the current transformer of the state detection unit and the power quality monitoring chip to judge whether the normally open contact of the contactor is disconnected, if yes, end the operation; if not, the contactor armature does not release the fault alarm and indication, and then end the operation . 6. The switching method of the intelligent capacitor switching composite switch according to claim 5, characterized in that: the input command of the manual switching switch has priority.