Large capacity power capacitors

Abstract

This invention discloses a large-capacity power capacitor, a reactive power compensation capacitor that dynamically connects and disconnects individual capacitors according to load demand. The principle of the reactive power compensation capacitor: It uses EPCOS single-phase capacitors and electrolytic capacitors as compensators to adjust the power factor in the system. A MOS3083 optocoupler is used for control to connect and disconnect the capacitors; the pre-charging block uses a series diode 1N5407 and a 220-ohm 100W resistor to achieve a stable charging process for the capacitors. The controller, based on the measurement of the load reactive power and the analysis of the grid voltage, achieves efficient reactive power compensation through precise control and stable operation. The reactive power compensation capacitor of this invention can achieve precise control and stable operation, improve energy utilization, reduce power loss, and effectively compensate for reactive power.

Description

Technical Field

[0001] The invention relates to a large-capacity power capacitor. Background Art

[0002] The power system refers to a system consisting of power plants, substations, transmission lines, distribution grids and end users, which is used to transmit electrical energy from power plants to users. It is a complex power grid that involves the generation, transmission, distribution and use of electricity.

[0003] In the power system, reactive power is a kind of power that cannot do work, and there is a certain loss and energy waste in the distribution network. The traditional method of reactive power compensation is mainly achieved through capacitor banks. The capacitors are connected to the power grid and the reactive power compensation and regulation are achieved by adjusting the capacity of the capacitors. However, the capacity of the traditional capacitor bank is small. When the capacitor is overloaded during the transient process, the battery reliability of the capacitor and the switching element is reduced; it cannot meet the large-capacity reactive power compensation needs, which increases the loss of electric energy and reduces the stability of the power system. Therefore, we make improvements to this and propose a large-capacity power capacitor. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a large-capacity power capacitor, comprising an electrode and a control module, wherein the electrode is connected to a dielectric, the electrode extends to the outside of a capacitor housing and is connected to a lead, and the lead is connected to the capacitor housing: the control module is provided with a circuit chip and a circuit board, a temperature sensor is provided on the circuit board, the circuit board is connected to a pre-charging unit through a semi-controlled thyristor switch, the pre-charging unit charges the ST capacitor to the amplitude of a power supply voltage, the circuit voltage passes through a maximum value, the voltage amplitude of the pre-charging unit is connected to an external circuit with an auxiliary capacitor of the same capacity, the semi-controlled thyristor switch disconnects and changes the instantaneous voltage of the connection of the capacitor, and the circuit on the circuit board is connected to a reactive power compensator.

[0005] As a preferred technical solution of the present invention, a transient process module is formed by connecting to the power grid through a half-controlled thyristor switch, and the transient process module includes a capacitor C; connected to the power grid through a half-controlled thyristor switch and a pre-charging unit, and connected to the capacitor of the transient capacitance unit; the signal generation of the first switch and the second switch is performed by the control circuit.

[0006] As a preferred technical solution of the present invention, the transient process module also includes a transient capacitance unit, which is connected to the power grid through a CT capacitor, and the CT capacitor is turned off at the same time, and the main capacitor is turned on; C is the transient change process formed by the voltage u(t) and the current i(t) when the capacitor is connected; the parameters of the TM-630 / 6 transformer are: e(t)-sinusoidal EMF with an amplitude of 320V and a frequency of 50Hz, R=2,5mΩ, L=40μH; the power grid load resistance Zh=(1Ohm+5mH in series); the capacity of the compensation capacitor C1=C2=..=Cп=CT=600μF; until the moment of time t=0, the capacitor C1 corresponds to the capacity of the compensator of 10kVA; at time t=0, the capacitor C2 with an initial voltage of zero is connected.

[0007] As a preferred technical solution of the present invention, the electrode is connected to the lead wire by welding, and the lead wire passes through a hole of the capacitor housing and is fixed to the capacitor housing by crimping or welding.

[0008] As a preferred technical solution of the present invention, the electrode includes an anode terminal and a cathode terminal, the anode terminal and the cathode terminal are respectively connected to leads, and the electrode material is copper foil.

[0009] As a preferred technical solution of the present invention, the reactive power compensator adopts 5 single-phase capacitors (C1..C5), each of which has a voltage of 230V and a capacity of 10kVA; two parallel 330μF x400V electrolytic capacitors are used as ST capacitors; buttons S1..S5 are made of thyristor 40TPS08 and controlled by MOS3083 optical coupler, and button ST uses a diode bridge.

[0010] As a preferred technical solution of the present invention, the diode bridge is made of KBPC5010W and IGBT type IRG4PSH71U, and is controlled by a driver with optical decoupling type FOD3120, and the voltage control and control signal formation are performed by a single-chip microcontroller ATMEL ATmega48PA-PU with a clock frequency of 20MHz.

[0011] As a preferred technical solution of the present invention, it also includes a controller, which generates a key control signal by measuring the reactive power of the load and analyzing the grid voltage. The controller monitors the grid voltage, the transition of the maximum voltage, and issues a command to turn on the ST key, monitors the moment when the voltage on the capacitor C1 and ST is balanced, and generates a signal to turn on the S1 key and turn off the ST key.

[0012] As a preferred technical solution of the present invention, the pre-charging unit uses a series-connected diode 1N5407 and a 220 ohm 100W resistor, with a switching frequency of twice per second, which is controlled by the time constant of the ST capacitor charging.

[0013] By adopting the above technical solution, the controller generates key control signals based on the measurement of load reactive power and the analysis of grid voltage. When a capacitor needs to be connected to the grid, the controller monitors the maximum value change of the grid voltage and issues a command to open the ST key. After the ST key is turned on, capacitor C1 starts to charge, and a stable charging process is achieved through the pre-charging block. When the voltage on capacitor C1 and ST is balanced, the controller generates a signal to turn on the S1 key and turn off the ST key to connect capacitor C1 to the grid. Through the precise control of the controller, the reactive power compensation capacitor can dynamically connect and disconnect each capacitor according to load demand. Principle of reactive power compensation capacitor: Reactive power compensation capacitor uses (EPCOS) single-phase capacitors and electrolytic capacitors as compensators to adjust the power factor in the system. MOS3083 optical coupler is used for control to achieve the connection and disconnection of capacitors.

[0014] The key ST is made of diode bridge KBPC5010W and IGBT type IRG4PSH71U, and is controlled by a driver with optical decoupling type FOD3120 to control the charging and discharging of the capacitor. The pre-charging block is in the form of a series diode 1N5407 and a 220 ohm 100W resistor to achieve a stable charging process of the capacitor. The controller achieves efficient reactive power compensation through precise control and stable operation based on the measurement of load reactive power and the analysis of grid voltage. The reactive power compensation capacitor of the present invention can achieve precise control and stable operation, improve energy utilization, reduce power loss, and effectively perform reactive power compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a circuit diagram of the compensator of the present invention;

[0016] Figure 2 is a curve diagram of voltage u(t) and current i(t) of the present invention;

[0017] Figure 3 It is the transient current component diagram of voltage u(t) and current i(t) of the present invention;

[0018] Figure 4 is a block diagram of a reactive power compensator of the present invention;

[0019] Figure 5 The structure diagram of the electrode, dielectric and lead wire of the present invention is shown;

[0020] Figure 6This is a structural diagram of the control module of the present invention;

[0021] Figure 7 It is a three-dimensional structural diagram of the present invention;

[0022] Figure 8 It is a local structure diagram of the electrode of the present invention;

[0023] Fig. 9 This is a logic block diagram of the transient process module of the present invention. DETAILED DESCRIPTION

[0024] The implementation example of the large-capacity power capacitor of the present invention is Figure 1-9 As shown: it includes an electrode 1 and a control module 2, the electrode 1 is connected to the dielectric 3, the electrode 1 extends to the outside of the capacitor housing 4 and is connected to the lead 5, the connection between the lead 5 and the capacitor housing 4: the control module 2 is provided with a circuit chip 21 and a circuit board 22, the circuit board 22 is provided with a temperature sensor 23, the circuit board 22 is connected to the pre-charging unit 7 through a half-controlled thyristor switch 6, the pre-charging unit 7 charges the ST capacitor to the amplitude of the power supply voltage, the circuit voltage passes the maximum value, the voltage amplitude of the pre-charging unit 7 is connected to the external circuit with the auxiliary capacitor of the same capacity, the half-controlled thyristor switch 6 disconnects and the instantaneous voltage of the connection of the commutation capacitor, and the circuit board 22 is connected with a reactive power compensator 24. It is connected to the power grid through the half-controlled thyristor switch 6 to form a transient process module, which includes a capacitor C; it is connected to the power grid through the half-controlled thyristor switch 6 and the pre-charging unit 7, and is connected to the capacitor of the transient capacitance unit; the signal generation of the first switch and the second switch is performed by the control circuit.

[0025] The transient process module also includes a transient capacitance unit, which is connected to the power grid through a CT capacitor. The CT capacitor is turned off at the same time and the main capacitor is turned on. C is the transient change process formed by the voltage u(t) and the current i(t) when the capacitor is connected. The parameters of the TM-630 / 6 transformer are: e(t)-sinusoidal EMF with an amplitude of 320V and a frequency of 50Hz, R=2,5mΩ, L=40μH; the power grid load resistance Zh=(1Ohm+5mH in series); the capacity of the compensation capacitor C1=C2=..=Cп=CT=600μF; until the moment of time t=0, the capacitor C1 corresponds to the capacity of the compensator of 10kVA; at time t=0, the capacitor C2 with an initial voltage of zero is connected.

[0026] The electrode 1 is connected to the lead 5 by welding, and the lead 5 passes through the hole 8 of the capacitor housing 4 and is fixed to the capacitor housing 4 by crimping or welding. The electrode 1 includes an anode terminal and a cathode terminal, and the anode terminal and the cathode terminal are respectively connected to the lead 5, and the material of the electrode 1 is copper foil.

[0027] The reactive power compensator 24 uses 5 single-phase capacitors (C1..C5), each with a voltage of 230V and a capacity of 10kVA; two parallel 330μF x 400V electrolytic capacitors are used as ST capacitors; buttons S1..S5 are made of thyristors 40TPS08 and controlled using MOS3083 optical couplers, and buttons ST use diode bridges. The diode bridge is made of KBPC5010W and IGBT type IRG4PSH71U, and is controlled by a driver with optical decoupling type FOD3120, and the voltage control and control signal formation are performed by a single-chip microcontroller ATMEL ATmega48PA-PU with a clock frequency of 20MHz.

[0028] The controller generates key control signals by measuring the reactive power of the load and analyzing the grid voltage. The controller monitors the grid voltage, the transition of the maximum voltage, and issues a command to open the ST key. It monitors the moment when the voltage on the capacitor C1 and ST is balanced, and generates signals to open the S1 key and close the ST key. The pre-charging unit 7 uses a series diode 1N5407 and a 220 ohm 100W resistor. The switching frequency is twice per second, which is controlled by the time constant of the ST capacitor charging.

[0029] The dielectric 3 inside the capacitor plays the role of storing electrical energy. Common dielectric 3 materials include ceramic, polyethylene, polypropylene, and polyimide. Different dielectrics 3 have different characteristics and performances, and suitable dielectric 3 materials can be selected according to specific application requirements. The electrode 1 of the capacitor is made of a conductive material, and the electrode 1 material is copper foil. The capacitor is usually composed of two electrodes 1, one is the anode (positive electrode) and the other is the cathode (negative electrode). An electric field is formed between the electrode 1 and the dielectric 3, thereby storing electrical energy. The lead 5 of the capacitor is used to connect the capacitor to the circuit. The lead 5 is usually made of a conductive material. The capacitor housing 4 is usually made of an insulating material to protect the internal structure and the dielectric 3. The capacitor housing 4 can have different shapes and sizes to adapt to different installation and use requirements. The internal structure of the capacitor is composed of the dielectric 3, the electrode 1, the lead 5 and the capacitor housing 4. Through the mutual cooperation and combination of these parts, the function of storing and releasing electrical energy is realized. The specific internal structure design can be adjusted and optimized according to the type of capacitor and application requirements.

[0030] In the structure of the capacitor, the following connection relationship exists between the dielectric 3, the electrode 1, the lead 5 and the capacitor housing 4: Connection between the dielectric 3 and the electrode 1: The dielectric 3 is usually in the form of a sheet or a film, and is completely attached to the electrode 1. Usually, a conductive layer or metal foil is coated on the surface of the dielectric 3 as the electrode 1 to ensure good contact between the electrode 1 and the dielectric 3. The connection between the dielectric 3 and the electrode 1 is usually achieved by coating or bonding. Connection between the electrode 1 and the lead 5: The electrode 1 of the capacitor is connected to the external circuit through the lead 5. The electrode 1 usually extends to the outside of the capacitor housing 4 and is connected to the lead 5. The lead 5 can be connected to the electrode 1 by welding, threading or crimping to ensure reliable connection between the capacitor and the circuit. Connection between the lead 5 and the capacitor housing 4: The lead 5 passes through the capacitor housing 4 and is connected to the capacitor housing 4. The connection method is usually that the lead 5 passes through the hole 8 of the capacitor housing 4 and is then fixed to the capacitor housing 4 by welding, crimping or fastening. This ensures good electrical and mechanical connection between the lead 5 and the capacitor housing 4.

[0031] The reactive power compensation capacitors include (EPCOS) single-phase capacitors (C1..C5) with a nominal voltage of 230V and a capacity of 10kVA each. In addition, two parallel 330μF x 400V electrolytic capacitors are included as ST capacitors. The buttons S1..S5 are made of thyristors 40TPS08 and controlled using MOS3083 optocouplers. The buttons ST are made using diode bridges KBPC5010W and IGBT class IRG4PSH71U and are controlled by drivers with optical decoupling type FOD3120. The voltage control and the formation of the control signals are performed by a single-chip microcontroller ATMEL ATmega48PA-PU with a clock frequency of 20MHz. The pre-charge block in the actual implementation is in the form of a series diode 1N5407 and a 220 ohm 100W resistor. At the same time, the number of switches is limited to twice per second by software to overcome the problems caused by the time constant of the ST capacitor charging. If the speed needs to be increased, the power of the pre-charge unit 7 is increased. The controller generates key control signals based on the measurement of load reactive power and the analysis of grid voltage. For example, if the S1 key is needed to connect capacitor C1 to the grid, the controller monitors the maximum value change of the grid voltage and issues a command to open the ST key. Then, when the voltage balance on capacitors C1 and ST is detected, a signal to open the S1 key and close the ST key is generated. This completes the process of connecting capacitor C1 to the grid.

[0032] Working principle of the present invention: Working process of reactive power compensation capacitor: The controller generates key control signals based on the measurement of load reactive power and analysis of grid voltage. When a capacitor needs to be connected to the grid, such as C1, the controller monitors the maximum value change of the grid voltage and issues a command to open the ST key. After the ST key is turned on, capacitor C1 starts to charge, and a stable charging process is achieved through the pre-charging block. When the voltage on capacitor C1 and ST is balanced, the controller generates a signal to turn on the S1 key and turn off the ST key to connect capacitor C1 to the grid. Through the precise control of the controller, the reactive power compensation capacitor can dynamically connect and disconnect each capacitor according to load requirements. Principle of reactive power compensation capacitor: Reactive power compensation capacitor uses (EPCOS) single-phase capacitors and electrolytic capacitors as compensators to adjust the power factor in the system. Buttons S1..S5 are made of thyristor 40TPS08 and controlled by MOS3083 optical coupler to achieve the connection and disconnection of capacitors. The key ST is made of a diode bridge KBPC5010W and an IGBT type IRG4PSH71U, and is controlled by a driver with optical decoupling type FOD3120, which is used to control the charging and discharging of the capacitor. The voltage control and the formation of the control signal are performed by a single-chip microcontroller ATMEL ATmega48PA-PU with a clock frequency of 20MHz, which is used to monitor the load reactive power and the grid voltage and generate key control signals. The pre-charging block is in the form of a series diode 1N5407 and a 220 ohm 100W resistor to achieve a stable charging process of the capacitor. The controller realizes efficient reactive power compensation through precise control and stable operation based on the measurement of the load reactive power and the analysis of the grid voltage. Through the above working process and principle, the reactive power compensation capacitor of the present invention can achieve precise control and stable operation, improve energy utilization, reduce power loss, and effectively perform reactive power compensation.

[0033] The above embodiment is only a large-capacity power capacitor of a preferred specific embodiment of the present invention. The usual changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are all included in the protection scope of the present invention.

Claims

1. A large-capacity power capacitor, comprising electrodes and a control module, characterized in that: The electrode is connected to the dielectric, the electrode extends to the outside of the capacitor housing and is connected to the lead, the lead is connected to the capacitor housing: the control module is provided with a circuit chip and a circuit board, the circuit board is provided with a temperature sensor, the circuit board is connected to a pre-charging unit through a semi-controlled thyristor switch, the pre-charging unit charges the ST capacitor to the amplitude of the power supply voltage, the circuit voltage passes through the maximum value, the voltage amplitude of the pre-charging unit is connected to the external circuit with an auxiliary capacitor of the same capacity, the semi-controlled thyristor switch disconnects and the instantaneous voltage of the connection of the commutation capacitor, and the circuit on the circuit board is connected with a reactive power compensator; The reactive power compensator uses 5 single-phase capacitors (C1..C5), each with a voltage of 230V and a capacity of 10kVA; two parallel 330μF x 400 V electrolytic capacitors are used as ST capacitors; buttons S1..S5 are made of thyristors 40TPS08 and controlled by MOS3083 optical couplers, and the button ST uses a diode bridge; The controller also includes a controller, which generates a key control signal by measuring the reactive power of the load and analyzing the grid voltage. The controller generates a signal for turning on the S1 key and turning off the ST key by monitoring the grid voltage, the transition of the maximum voltage, and issuing a command to turn on the ST key, monitoring the moment when the voltage on the capacitor C1 and ST is balanced; The first switch and the second switch are connected to the grid through a half-controlled thyristor switch to form a transient process module, the transient process module includes a capacitor C; the first switch and the second switch are connected to the grid through a half-controlled thyristor switch and a pre-charging unit, and the capacitor is connected to the transient capacitor unit; the signal generation of the first switch and the second switch is performed by the control circuit; The transient process module also includes a transient capacitance unit, which is connected to the power grid through a CT capacitor, and the CT capacitor is turned off at the same time, and the main capacitor is turned on; C is the transient change process formed by the voltage u(t) and the current i(t) when the capacitor is connected; the parameters of the TM-630 / 6 transformer: e(t)-sinusoidal EMF with an amplitude of 320 V and a frequency of 50 Hz, R=2,5 mΩ, L=40μH; the power grid load resistance Zh=(1 Ohm+5 mH in series); the capacity of the compensation capacitor C1=C2=..=Cп=CT=600μF; until the moment of time t=0, the capacitor C1 corresponds to the capacity of the compensator of 10kVA; at time t=0, the capacitor C2 with an initial voltage of zero is connected.

2. The large-capacity power capacitor according to claim 1, characterized in that: The electrode is connected to the lead wire by welding, and the lead wire passes through a hole of the capacitor shell and is fixed on the capacitor shell by crimping or welding.

3. The large-capacity power capacitor according to claim 1 is characterized in that: The electrode comprises an anode terminal and a cathode terminal, the anode terminal and the cathode terminal are respectively connected to leads, and the electrode material is copper foil.

4. The large-capacity power capacitor according to claim 1, characterized in that: The diode bridge is made of KBPC5010W and IGBT type IRG4PSH71U and is controlled by a driver with optical decoupling type FOD3120, the voltage control and the formation of the control signals are performed by a single-chip microcontroller ATMEL ATmega48PA-PU with a clock frequency of 20 MHz.

5. The large-capacity power capacitor according to claim 1, characterized in that: The pre-charging unit uses a series diode 1N5407 and a 220 ohm 100W resistor, with a switching frequency of twice per second, which is controlled by the time constant of the ST capacitor charging.

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