CN104362702A - Power supply system of transformer substation - Google Patents

Abstract

The invention relates to the technical field of new energy power generation control, in particular to a power supply system that uses a photovoltaic power generation system to supply power to a DC system in a substation. It includes load, mains power grid, control switching device, storage battery, several charge and discharge controllers and solar panels. The solar panel supplies power to the battery through the charge and discharge controller. Power supply; the charge and discharge controller includes a charge management circuit, a modulation circuit, a power supply management circuit and a main controller. The solar panel charges the battery through the conversion of the charge management circuit and the modulation circuit in turn, and the battery is controlled by the power supply management circuit to control the switching device. powered by. The invention can control the charge and discharge of the battery through the control of the charge and discharge controller to ensure the normal operation of the control switching device and realize the function conversion of mains power supply, photovoltaic power generation and grid-connected power supply by using the control switching device, thereby ensuring the safety of the substation. normal work.

Description

A substation power supply system

technical field

The invention relates to the technical field of new energy power generation control, in particular to a power supply system that uses a photovoltaic power generation system to supply power to a DC system in a substation.

Background technique

Photovoltaic grid-connected power generation technology is a new technology that has emerged in recent years. Compared with traditional kerosene and oil-based electricity, it has many advantages such as environmental protection, no energy consumption, and reusability. It will be the focus of energy strategy development in the future.

In a substation with photovoltaic grid-connected system, the control switching device is a key device to realize the function switching of grid-connected power generation, mains power supply and DC power supply of the substation; therefore, it is necessary to propose an improvement plan for the existing power supply system of the substation , to use the photovoltaic power generation system to ensure the normal operation of the control switching device or other DC loads in the substation.

Contents of the invention

In view of the deficiencies in the prior art above, the purpose of the present invention is to provide a substation power supply system with simple system structure, stable voltage output and high reliability.

In order to achieve the above object, the present invention adopts the following technical solutions:

A substation power supply system, which includes a load, a mains power grid, a control switching device, a storage battery, several charge and discharge controllers, and several solar panels corresponding to the charge and discharge controllers. The corresponding charging and discharging controller supplies power to the storage battery, and the storage battery and the mains grid supply power to the load by controlling the conversion of the switching device;

The charge and discharge controller includes a charge management circuit, a modulation circuit, a power supply management circuit and a main controller. The solar panel is sequentially converted by the charge management circuit and the modulation circuit generates +5V power to charge the battery, and the battery is powered The control of the management circuit supplies power to the control switching device, and the main controller collects the voltage value of the storage battery and controls the charging of the storage battery through the modulation circuit.

Preferably, the main controller is also respectively connected with a power detection circuit and an overcurrent protection circuit.

Preferably, the main controller includes a F330 single-chip microcomputer.

Preferably, the charge management circuit includes a first diode, a second diode, a first triode and a first switch tube, and the first diode and the second diode are connected in parallel to the solar energy Between the battery board and the source of the first switch tube, a third diode and a first resistor are connected in series between the source and drain of the first switch tube, and a first resistor is connected between the source and the gate. Two resistors, the drain of the first switching tube is connected to the storage battery, the grid is connected to the collector of the first triode, the emitter of the first triode is grounded, and the base is connected to the output of the modulation circuit through the third resistor end;

The charging management circuit further includes a fourth resistor and a fifth resistor, the fourth resistor is connected between the drain of the first switch tube and the main controller and grounded through the fifth resistor.

Preferably, the power supply management circuit includes a second switch tube and a second triode, a sixth resistor is connected between the source and the gate of the second switch tube, and the gate of the second switch tube is connected to The collector of the second triode, the emitter of the second triode are grounded, the base is connected to the seventh resistor, and the source of the second switching tube is connected to both ends of the storage battery.

Due to the adoption of the above scheme, the present invention can continuously control the charging and discharging of the storage battery through the control of the charging and discharging controller, so as to ensure the normal operation of the control switching device and use the control switching device to realize mains power supply, photovoltaic power generation and grid connection The function conversion of power supply ensures the normal operation of the substation; its structure is simple, its reliability is high, and it has strong practicability.

Description of drawings

Fig. 1 is a system schematic diagram of an embodiment of the present invention;

Fig. 2 is a system schematic diagram of a charging and discharging controller according to an embodiment of the present invention;

Fig. 3 is a circuit structure diagram of a charging and discharging controller according to an embodiment of the present invention.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways defined and covered by the claims.

As shown in Figures 1 to 3, a substation power supply system provided by this embodiment includes a load 1, a mains power grid 2, a control switching device 3, a lithium-ion battery as a storage battery 4, and several charge and discharge controllers 5 And several solar panels 6 corresponding to the charging and discharging controller 5; wherein, several solar panels 6 supply power to the storage battery 4 through the corresponding charging and discharging controller 5, and the storage battery 4 and the mains power grid 2 control the switching device 3 to supply power to the load 1; at the same time, the charging and discharging controller 5 includes a charging management circuit a, a modulation circuit b that outputs PWM waves, a power supply management circuit c, and a main controller d, and the solar panel 6 passes through the charging management circuit a sequentially. The conversion and modulation circuit b generates +5V power to charge the storage battery 4, and the storage battery 4 supplies power to the control switching device 3 through the control of the power supply management circuit c, while the main controller d collects the voltage value of the storage battery 4 and supplies power to the storage battery 4 through the modulation circuit b. 4 charging is controlled. In this way, the battery 4 can be continuously charged and discharged through the control of the charge and discharge controller 5, so as to ensure the normal operation of the control switching device 3 and use the control switching device 3 to realize commercial power supply, photovoltaic power generation and grid-connected power supply. Function conversion, thus ensuring the normal operation of the substation.

In order to enrich the functions of the charging and discharging controller 5 and ensure the reliability and accuracy of its functions, the main controller d in this embodiment is also connected with a power detection circuit e and an overcurrent protection circuit f respectively, and both circuits can be used in the field The more common circuit structures in

In order to ensure the performance of the charging point electric controller 5 and realize precise control, the main controller d of this embodiment includes a F330 single-chip microcomputer.

Further, in order to rationally optimize the function of the charge and discharge controller 5 and to simplify the circuit structure to the greatest extent, the charge management circuit a of this embodiment includes a first diode D1, a second diode D2, a first triode Tube Q1 and the first switch tube U1; wherein, the first diode D1 and the second diode D2 are connected in parallel and connected between the solar panel 6 and the source of the first switch tube U1, and the first switch tube U1 A third diode D3 and a first resistor R1 are connected in series between the source and the drain, a second resistor R2 is connected between the source and the gate, and the drain of the first switching tube U1 is connected to the storage battery 4 and the gate. Connect the collector of the first triode Q1, the emitter of the first triode Q1 is grounded, and the base is connected to the output terminal of the modulation circuit b through the third resistor R3; at the same time, the charging management circuit a also includes a fourth resistor R4 and The fifth resistor R5 and the fourth resistor R4 are connected between the drain of the first switching transistor U1 and the main controller d and grounded through the fifth resistor R5.

In this way, the solar battery panel 6 firstly supplies power to the whole system after being stepped down by the first diode D1 and the second diode D2. The second resistor R2, the first switching tube U1, the third resistor R3 and the first three The pole tube Q1 constitutes the charging circuit of the battery 4. The main controller d generates an 8-bit PWM wave and controls the duty ratio through the modulation circuit b to control the on and off of the first triode Q1, and then control the first switch tube U1 The turn-on and turn-off of the battery 4 can realize the charging control and management of the storage battery 4 . The third diode D3 and the first resistor R1 constitute the trickle charging circuit of the storage battery 4. After continuous rainy days, the remaining power of the storage battery 4 is not enough for the control switching device 3 to work. This trickle circuit causes the recovery of the battery 4 voltage. The role is to control the size of the trickle charging current by setting the resistance value of the first resistor R1; if the first resistor R1 is too small, then the loop current is relatively large, and the first triode Q1 and the first switch tube The PWM control function of U1 basically does not play any role. If the first resistor R1 cannot perform trickle charging when the battery 4 needs to be trickle charged, it may cause the entire system to fail to start normally; therefore, in this embodiment The preferred resistance value of the first resistor R2 is 100 ohms. The fourth resistor R4 and the fifth resistor R5 constitute the measuring resistance of the storage battery 4, and the voltage value of the storage battery 4 can be obtained by the main controller d collecting the voltage at this point (that is, the point TP1 in the figure). The controller d controls the modulation circuit b to realize the duty ratio control.

Further, the power supply management circuit c of this embodiment includes a second switch tube U2 and a second triode Q2, a sixth resistor R6 is connected between the source and the gate of the second switch tube U2, and the second switch tube U2 The gate of the second transistor U2 is connected to the collector of the second transistor Q2, the emitter of the second transistor Q2 is grounded, the base is connected to the seventh resistor R7, and the source of the second switching tube U2 and the seventh resistor R7 are connected to the battery 4 both ends. In this way, a power supply circuit of the storage battery 4 can be formed, and by controlling the storage battery 4 to realize its power supply to the control switching device 3 , the impact on the load 1 can be minimized.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related All technical fields are equally included in the scope of patent protection of the present invention.

Claims (5)

1. A substation power supply system is characterized in that: it includes a load, a mains grid, a control switching device, a storage battery, several charge and discharge controllers and several solar panels corresponding to the charge and discharge controller, and several The solar panel supplies power to the storage battery through the corresponding charge and discharge controller, and the storage battery and the mains grid supply power to the load by controlling the conversion of the switching device; The charge and discharge controller includes a charge management circuit, a modulation circuit, a power supply management circuit and a main controller. The solar panel is sequentially converted by the charge management circuit and the modulation circuit generates +5V power to charge the battery, and the battery is powered The control of the management circuit supplies power to the control switching device, and the main controller collects the voltage value of the storage battery and controls the charging of the storage battery through the modulation circuit. 2. A substation power supply system according to claim 1, characterized in that: the main controller is also connected with a power detection circuit and an overcurrent protection circuit respectively. 3. A substation power supply system as claimed in claim 2, characterized in that: said main controller includes a F330 single-chip microcomputer. 4. A substation power supply system according to any one of claims 1-3, characterized in that: the charging management circuit includes a first diode, a second diode, a first triode and a second A switch tube, the first diode and the second diode are connected in parallel between the solar panel and the source of the first switch tube, and the source and drain of the first switch tube are sequentially connected A third diode and the first resistor are connected in series, a second resistor is connected between the source and the grid, the drain of the first switching tube is connected to the storage battery, and the grid is connected to the collector of the first triode, so The emitter of the first triode is grounded, and the base is connected to the output terminal of the modulation circuit through a third resistor; The charging management circuit further includes a fourth resistor and a fifth resistor, the fourth resistor is connected between the drain of the first switch tube and the main controller and grounded through the fifth resistor. 5. A substation power supply system as claimed in claim 4, characterized in that: said power supply management circuit comprises a second switch tube and a second triode, the source and gate of said second switch tube A sixth resistor is connected, the gate of the second switch tube is connected to the collector of the second triode, the emitter of the second triode is grounded, and the base is connected to the seventh resistor, and the second switch The source of the tube and the seventh resistor connect the two ends of the battery.