Direct-current power supply emergency system for transformer substation

Abstract

The invention relates to a direct-current power supply emergency system for a transformer substation, and belongs to the technical field of emergency power supplies. The system comprises a generator emergency starting power supply composed of a full-bridge switching power supply and a super capacitor, and a control system. The control system monitors the mains supply at ordinary times and supplements electric energy to the super capacitor through the full-bridge switching power supply, so that a generator starting loop keeps sufficient starting conditions. When voltage loss of the mains supply is detected, a starting command is immediately sent to a generator controller, generator outlet electrical parameters are monitored in real time, and when voltage and frequency of a generator outlet are normal, a switching command is sent to switch power supply of a direct-current system in a transformer substation to power supply of the generator. The problem that the generator cannot be started due to power shortage of the generator starting storage battery is solved. The touch screen can adjust various control parameters and display electrical operation parameters of each key part in real time.

Description

Technical Field

[0001] The invention relates to a direct current power supply emergency system for a transformer substation, belonging to the technical field of emergency power supplies. Background Art

[0002] In severe weather conditions in remote mountainous areas, emergency repair roads are blocked and it is impossible to reach the site for emergency repairs in time. Traditional emergency generator access and remote-controlled generator access systems require remote control or manual operation to disconnect all 0.4kV AC bus feeder air switches and AC bus incoming air switches before the generator can be started, which has high management costs. At the same time, the existing air switches are changed to remote-controlled air switches, and the investment cost is too high and not economical. In the startup process of this emergency system, there is no need to operate any existing AC air switches, and there is no need to reverse power to the main grid equipment, so the system is highly safe. Solve the problem of weak AC power supply systems for plants without main transformers, thereby improving the safety of equipment operation. Summary of the invention

[0003] The technical problem to be solved by the present invention is: the present invention provides a DC power supply emergency system for substations, which does not require the operation of any existing AC air switch during the startup process, does not involve reverse power supply to the main network equipment, and has high system safety. It solves the problem of weak AC power supply system for substations without main transformers, thereby improving the safety of equipment operation.

[0004] The technical solution of the present invention is: a DC power supply emergency system for a substation, including a full-bridge switching power supply, a generator emergency starting power supply composed of a super capacitor, and a control system;

[0005] The control system is used to monitor the mains power and replenish electric energy to the supercapacitor through a full-bridge switching power supply, so that the generator starting circuit maintains sufficient starting conditions; when the mains power loss is detected, a start command is immediately sent to the generator controller, and the generator outlet electrical parameters are monitored in real time. When the generator outlet voltage and frequency are normal, a switching command is issued to switch the DC system power supply in the substation to the generator power supply; the touch screen of the control system is used to adjust various control parameters and display the electrical operating parameters of key parts in real time.

[0006] Furthermore, the full-bridge switching power supply adopts a phase-shifted ZVS soft-switching full-bridge topology structure with an additional auxiliary resonant network; the lagging arm of the topology structure is connected in parallel with the auxiliary resonant network.

[0007] Further, the auxiliary resonant network includes an inductor La and capacitors Ca1, Ca2 and diodes Da1, Da2; the first end of the inductor La is connected between the upper tube and the lower tube of the lagging arm, specifically, the first end of the inductor La is connected to the first end of the upper tube of the lagging arm and the first end of the lower tube of the lagging arm, the second end of the inductor La is connected to the first ends of the capacitors Ca1 and Ca2 respectively, and the second end of the inductor La is also connected to the positive electrode of the diode Da1 and the negative electrode of Da2 respectively; the second ends of the capacitors Ca1 and Ca2 are connected to the second end of the upper tube of the lagging arm and the second end of the lower tube of the lagging arm respectively, the negative electrode of the diode Da1 and the positive electrode of Da2 are connected to the second end of the upper tube of the lagging arm and the second end of the lower tube of the lagging arm respectively, and the second end of the lower tube of the lagging arm is also grounded at the same time.

[0008] Furthermore, the supercapacitor is used as a generator starting battery.

[0009] Furthermore, the control system adopts STM32 series 32-bit high-performance and low-cost MCU as the main control chip, specifically adopts STM32F103 chip.

[0010] Furthermore, it also includes an electrical parameter detection circuit and a generator starting output circuit;

[0011] The electrical parameter detection circuit is used to collect the DC power used by the municipal power station, the voltage, frequency and phase parameters of the generator, and transmit the parameters to the control system through the SPI interface and MCU communication for data processing and judgment;

[0012] The generator start output circuit is used to start and stop the generator and switch the circuit breaker according to the command of the control system.

[0013] Furthermore, the electrical parameter detection circuit includes an RN7302 chip, capacitors C3, C4, C5, C6, C8, C9, C15, C16, C17, C18, resistors R11, R22, and a crystal oscillator X1; the AVCC terminal of the RN7302 chip is respectively connected to the first end of the resistor R22, the first ends of the capacitors C17 and C18, and the second end of R22 is connected to a +3.3V power supply; the second ends of the capacitors C17 and C18 are grounded, the REFV terminal of the RN7302 chip is respectively connected to the first ends of the capacitors C3 and C4, the second ends of the capacitors C3 and C4 are grounded, and the RN The VO terminal of the 7302 chip is respectively connected to the first ends of capacitors C5 and C6, and the second ends of capacitors C5 and C6 are grounded. The XI terminal of the RN7302 chip is respectively connected to the first end of capacitor C8, the first end of crystal oscillator X1, and the first end of resistor R11. The XO terminal of the RN7302 chip is respectively connected to the first end of capacitor C9, the second end of crystal oscillator X1, and the second end of resistor R11. The second ends of capacitors C8 and C9 are both grounded. The RSTN terminal of the RN7302 chip is respectively connected to the first ends of capacitors C15 and C16 and the +3.3V power supply; the second ends of capacitors C15 and C16 are grounded.

[0014] The beneficial effects of the present invention are: the present invention does not need to operate any existing AC air switch during the startup process, does not involve reverse power supply to the main grid equipment, and has high system safety. It solves the problem of weak AC power supply system for power plants without main transformers, thereby improving the safety of equipment operation.

[0015] The present invention can monitor the mains power and replenish the supercapacitor with electric energy through a full-bridge switching power supply, so that the generator starting circuit maintains sufficient starting conditions. When the mains power is detected to be depressurized, a start command is immediately sent to the generator controller, and the generator outlet electrical parameters are monitored in real time. When the generator outlet voltage and frequency are normal, a switching command is issued to switch the DC system power supply in the substation to the generator power supply. The problem of the generator not being able to start due to the lack of power in the generator starting battery is solved. The touch screen can adjust various control parameters and display the electrical operating parameters of key parts in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the DC power supply emergency system for a substation of the present invention;

[0017] Figure 2 It is a schematic diagram of the structure of the full-bridge switch voltage stabilizing circuit of the present invention;

[0018] Figure 3 It is a schematic diagram of the MCU system structure of the present invention;

[0019] Figure 4 It is a schematic diagram of the structure of the electrical parameter detection circuit of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0021] Example 1

[0022] like Figure 1-Figure 4 As shown, a DC power supply emergency system for a substation includes a full-bridge switching power supply, a generator emergency starting power supply composed of super capacitors, and a control system;

[0023] The control system is used to monitor the mains power and replenish electric energy to the supercapacitor through a full-bridge switching power supply, so that the generator starting circuit maintains sufficient starting conditions; when the mains power loss is detected, a start command is immediately sent to the generator controller, and the generator outlet electrical parameters are monitored in real time. When the generator outlet voltage and frequency are normal, a switching command is issued to switch the DC system power supply in the substation to the generator power supply; the touch screen of the control system is used to adjust various control parameters and display the electrical operating parameters of key parts in real time.

[0024] like Figure 2 The full-bridge switching voltage stabilizing circuit structure schematic diagram of the present invention is shown. The full-bridge switching power supply adopts a phase-shifted ZVS soft-switch full-bridge topology structure with an additional auxiliary resonant network, which greatly improves the efficiency and reliability of the voltage stabilizing power supply; the lagging arm parallel auxiliary resonant network of the topology structure. The auxiliary resonant network includes an inductor La, capacitors Ca1, Ca2, and diodes Da1, Da2; the first end of the inductor La is connected between the upper tube and the lower tube of the lagging arm, specifically, the first end of the inductor La is connected to the first end of the upper tube of the lagging arm and the first end of the lower tube of the lagging arm, the second end of the inductor La is connected to the first end of the capacitors Ca1 and Ca2 respectively, and the second end of the inductor La is also connected to the positive electrode of the diode Da1 and the negative electrode of Da2 respectively; the second ends of the capacitors Ca1 and Ca2 are connected to the second end of the upper tube of the lagging arm and the second end of the lower tube of the lagging arm respectively, the negative electrode of the diode Da1 and the positive electrode of Da2 are connected to the second end of the upper tube of the lagging arm and the second end of the lower tube of the lagging arm respectively, and the second end of the lower tube of the lagging arm is also grounded at the same time.

[0025] This topology is easier to achieve soft switching of the lagging arm than the traditional ZVS phase-shifted full bridge; the auxiliary resonant network does not interfere with the main power conversion and is not affected by the load current. The principle is: when the lower tube M4 of the lagging arm is turned off, the auxiliary inductor current and the primary current flow into the node between M2 and M4 at the same time, and when the upper tube M2 of the lagging arm is turned off, they flow out of the node at the same time. That is, the two currents discharge the parallel capacitor at the same time, and can drain the charge in the parallel capacitor before M2 or M4 is turned on under various load currents, especially light load or no load, and smoothly achieve ZVS.

[0026] Furthermore, the supercapacitor is used as a generator starter battery. It has electrical properties that ordinary batteries do not have. First, it has a small internal resistance and can output a large current of kiloamperes, which can easily start a diesel generator set. Secondly, it has a very small leakage and a long life. After being fully charged, it can store electricity for a long time, at least in years. Moreover, it does not have a chemical reaction inside an ordinary battery, which leads to a big defect in storing electricity and service life. In addition, it also has a fast charging function. As long as the charging equipment allows, it can be fully charged instantly in theory. In fact, a charging current of 100 amperes or even hundreds of amperes is acceptable, and the charging time can be shortened to tens of seconds to a few minutes.

[0027] Further, the control system adopts STM32 series 32-bit high-performance and low-cost MCU as the main control chip, specifically adopting STM32F103 chip. STM32F103 is a microcontroller based on ARMCortex-M3 core launched by STMicroelectronics, belonging to the low-end 32-bit ARM microcontroller series. This series of chips is widely used in industrial control, medical equipment, smart home and other fields due to its high performance, low power consumption, rich peripherals and diversified interfaces.

[0028] The main features of the STM32F103 chip include:

[0029] High performance: Based on the Cortex-M3 core, the maximum frequency can reach 72MHz, providing performance up to 1.25DMips / MHz, supporting hardware coprocessors, and is suitable for high-speed computing tasks and data processing.

[0030] Low power consumption: low power consumption design, intelligent clock management module and context switching technology are adopted to effectively save power consumption.

[0031] Diversified interfaces: Provides up to 80 external I / O ports and supports multiple communication interfaces such as SPI, I2C, USART, etc., to facilitate system integration.

[0032] Security: Supports hardware encryption algorithms and verification mechanisms to ensure system security.

[0033] Complete development environment: supports a variety of software development tools and debugging tools, such as Keil, IAR, etc., as well as ST's own development tool set, which is convenient for developers to develop and debug.

[0034] In addition, the STM32F103 chip also integrates multiple peripheral functions such as timers, CAN, ADC, SPI, I2C, USB, UART, and multiple low-power modes such as sleep, shutdown, and standby to meet different application requirements. In terms of power management, it supports 2.0-3.6V power supply and I / O pins, and has functions such as power-on / power-off reset (POR / PDR) and programmable voltage monitor (PVD)12.

[0035] The STM32F103 series chips can be divided into three categories according to the size of the on-chip Flash: small capacity (16K and 32K), medium capacity (64K and 128K), and large capacity (256K, 384K, and 512K), to meet the storage capacity requirements of different applications1. With the powerful functions of STM32F103, the system can be fully intelligently monitored and controlled. Figure 3 .

[0036] The present invention also includes an electrical parameter detection circuit and a generator starting output circuit; the electrical parameter detection circuit is as follows Figure 4 As shown;

[0037] The electrical parameter detection circuit is used to collect the DC power used by the municipal power station, the voltage, frequency and phase parameters of the generator, and transmit the parameters to the control system through the SPI interface and MCU communication for data processing and judgment;

[0038] The generator start output circuit is used to start and stop the generator and switch the circuit breaker according to the command of the control system.

[0039] Furthermore, the electrical parameter detection circuit includes an RN7302 chip, capacitors C3, C4, C5, C6, C8, C9, C15, C16, C17, C18, resistors R11, R22, and a crystal oscillator X1; the AVCC terminal of the RN7302 chip is respectively connected to the first end of the resistor R22, the first ends of the capacitors C17 and C18, and the second end of R22 is connected to a +3.3V power supply; the second ends of the capacitors C17 and C18 are grounded, the REFV terminal of the RN7302 chip is respectively connected to the first ends of the capacitors C3 and C4, the second ends of the capacitors C3 and C4 are grounded, and the RN The VO terminal of the 7302 chip is respectively connected to the first ends of capacitors C5 and C6, and the second ends of capacitors C5 and C6 are grounded. The XI terminal of the RN7302 chip is respectively connected to the first end of capacitor C8, the first end of crystal oscillator X1, and the first end of resistor R11. The XO terminal of the RN7302 chip is respectively connected to the first end of capacitor C9, the second end of crystal oscillator X1, and the second end of resistor R11. The second ends of capacitors C8 and C9 are both grounded. The RSTN terminal of the RN7302 chip is respectively connected to the first ends of capacitors C15 and C16 and the +3.3V power supply; the second ends of capacitors C15 and C16 are grounded.

[0040] When the MCU determines that the generator should be started, a start signal is sent from the MCU to the generator control system to start the generator. When the generator speed and voltage are stable, a dual power switching command is immediately sent to the switching circuit breaker to switch the station DC system to the generator power supply. When the MCU determines that the generator should be stopped, a switching signal is sent to switch the station DC system to the mains power supply, and then a shutdown signal is sent to the generator control system to stop the generator.

[0041] The control system usually monitors the mains power and replenishes the supercapacitor with power through a full-bridge switching power supply to keep the generator starting circuit in sufficient starting conditions. When the mains power is detected to be de-voltaged, a start command is immediately sent to the generator controller, and the generator outlet electrical parameters are monitored in real time. When the generator outlet voltage and frequency are normal, a switching command is issued to switch the DC system power supply in the substation to the generator power supply. This solves the problem of the generator not being able to start due to the lack of power in the generator starting battery. The touch screen can adjust various control parameters and display the electrical operating parameters of key parts in real time.

[0042] The specific embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A DC power supply emergency system for a substation, characterized by: Including full-bridge switching power supply, generator emergency starting power supply and control system composed of super capacitor; The control system is used to monitor the mains power and replenish electric energy to the supercapacitor through a full-bridge switching power supply, so that the generator starting circuit maintains sufficient starting conditions; when the mains power loss is detected, a start command is immediately sent to the generator controller, and the generator outlet electrical parameters are monitored in real time. When the generator outlet voltage and frequency are normal, a switching command is issued to switch the DC system power supply in the substation to the generator power supply; the touch screen of the control system is used to adjust various control parameters and display the electrical operating parameters of key parts in real time.

2. The DC power supply emergency system for substation according to claim 1 is characterized in that: The full-bridge switching power supply adopts a phase-shifted ZVS soft-switching full-bridge topology structure with an auxiliary resonant network added; the lagging arm of the topology structure is connected in parallel with the auxiliary resonant network.

3. The DC power supply emergency system for substation according to claim 2 is characterized in that: The auxiliary resonant network includes an inductor La, capacitors Ca1, Ca2, and diodes Da1, Da2; the first end of the inductor La is connected between the upper tube and the lower tube of the lagging arm, specifically, the first end of the inductor La is connected to the first end of the upper tube of the lagging arm and the first end of the lower tube of the lagging arm, the second end of the inductor La is connected to the first ends of the capacitors Ca1 and Ca2 respectively, and the second end of the inductor La is also connected to the positive electrode of the diode Da1 and the negative electrode of Da2 respectively; the second ends of the capacitors Ca1 and Ca2 are connected to the second end of the upper tube of the lagging arm and the second end of the lower tube of the lagging arm respectively, the negative electrode of the diode Da1 and the positive electrode of Da2 are connected to the second end of the upper tube of the lagging arm and the second end of the lower tube of the lagging arm respectively, and the second end of the lower tube of the lagging arm is also grounded at the same time.

4. The DC power supply emergency system for substation according to claim 1 is characterized in that: The supercapacitor is used as a generator starting battery.

5. The DC power supply emergency system for substation according to claim 1 is characterized in that: The control system adopts the STM32 series 32-bit high-performance and low-cost MCU as the main control chip, specifically the STM32F103 chip.

6. The DC power supply emergency system for substation according to claim 1 is characterized in that: It also includes an electrical parameter detection circuit and a generator starting output circuit; The electrical parameter detection circuit is used to collect the DC power used by the municipal power station, the voltage, frequency and phase parameters of the generator, and transmit the parameters to the control system through the SPI interface and MCU communication for data processing and judgment; The generator start output circuit is used to start and stop the generator and switch the circuit breaker according to the command of the control system.

7. The DC power supply emergency system for substation according to claim 6 is characterized in that: The electrical parameter detection circuit includes an RN7302 chip, capacitors C3, C4, C5, C6, C8, C9, C15, C16, C17, C18, resistors R11, R22, and a crystal oscillator X1; the AVCC terminal of the RN7302 chip is respectively connected to the first end of the resistor R22 and the first ends of the capacitors C17 and C18, and the second end of R22 is connected to a +3.3V power supply; the second ends of the capacitors C17 and C18 are grounded, the REFV terminal of the RN7302 chip is respectively connected to the first ends of the capacitors C3 and C4, the second ends of the capacitors C3 and C4 are grounded, and the RN730 The VO terminal of the RN7302 chip is respectively connected to the first end of the capacitors C5 and C6, and the second ends of the capacitors C5 and C6 are grounded. The XI terminal of the RN7302 chip is respectively connected to the first end of the capacitor C8, the first end of the crystal oscillator X1, and the first end of the resistor R11. The XO terminal of the RN7302 chip is respectively connected to the first end of the capacitor C9, the second end of the crystal oscillator X1, and the second end of the resistor R11. The second ends of the capacitors C8 and C9 are both grounded. The RSTN terminal of the RN7302 chip is respectively connected to the first end of the capacitors C15 and C16 and the +3.3V power supply; the second ends of the capacitors C15 and C16 are grounded.

Images