CN108400650A - Power of alterating and direct current integral system - Google Patents

Abstract

The invention relates to an integrated AC and DC power supply system, comprising: an AC power supply system, a DC power supply system connected to batteries, and an AC uninterrupted power supply system connected to AC power equipment in offshore wind farms; one end of the DC power supply system is connected to the AC uninterrupted power supply system, and the other end is connected to the AC uninterruptible power supply system through the AC power system. Based on the application scenarios of offshore wind farms, by combining AC UPS, AC power systems and DC power systems into an integrated AC and DC power system, and sharing battery power supply, the structure of power equipment is simplified, integrated monitoring is realized, and improved The degree of automation of offshore wind farms is improved, and at the same time, automatic management and operation of the entire system can be carried out, effectively reducing the number and space of panel cabinets, reducing the workload of commissioning and maintenance costs.

Description

AC and DC power integrated system

technical field

The invention relates to the technical field of offshore wind farms, in particular to an integrated AC and DC power supply system.

Background technique

my country is rich in offshore wind energy resources, and the wind energy reserves that can be developed and utilized at a height of 10m (meters) offshore are about 750 million kW (kilowatts). Offshore wind power will become the focus of my country's future clean energy development. With the development of offshore wind power in my country, the distance is getting farther and larger, and the offshore booster station is the hub of offshore wind power transmission. The onshore centralized control center is for centralized monitoring at unattended and centralized control stations Indispensable monitoring system center in run mode.

In the traditional technology, the inventors found at least the following problems: on the one hand, the power resources of the offshore booster station and the land centralized control center cannot be considered as a whole, such as serious waste of storage battery configuration; on the other hand, different manufacturers The communication protocols provided by the subsystems are not compatible, and centralized monitoring and comprehensive analysis cannot be performed, which severely limits the level of centralized management and condition maintenance, resulting in a low degree of automatic monitoring of AC and DC power supplies, resulting in poor overall economic benefits and high investment costs.

Contents of the invention

Based on this, it is necessary to provide an integrated AC and DC power supply system for the problem that the power resources of offshore wind farms cannot be considered as a whole.

In order to achieve the above purpose, an embodiment of the present invention provides an integrated AC and DC power supply system, including: an AC power supply system, a DC power supply system connected to a battery, and an AC uninterruptible power supply system connected to the AC power equipment of an offshore wind farm;

One end of the DC power supply system is connected to the AC uninterruptible power supply system, and the other end is connected to the AC uninterruptible power supply system through the AC power supply system.

In one of the embodiments, it also includes a communication power screen connected to communication equipment;

One end of the communication power panel is connected to the DC power system, and the other end is connected to the DC power system through the AC power system.

In one of the embodiments, the AC uninterruptible power supply system includes a first AC uninterruptible power supply and a second AC uninterruptible power supply; the AC power supply system includes a first AC switch cabinet, a second AC switch cabinet, a first AC feeder cabinet, and a second AC switch cabinet. Two AC feeder cabinets; the DC power supply system includes a first DC feeder panel, a second DC feeder panel, a first DC charging panel, and a second DC charging panel;

The first DC charging screen is respectively connected to the first AC uninterruptible power supply and the first AC feeder cabinet through the first DC feeder cabinet, and is respectively connected to the first AC uninterruptible power supply and the first AC feeder cabinet through the first AC feeder cabinet. Switchgear;

The second DC charging panel is respectively connected to the second AC uninterruptible power supply and the second AC feeder cabinet through the second DC feeder cabinet, and is respectively connected to the second AC uninterruptible power supply and the second AC switch cabinet through the second AC feeder cabinet.

The first AC feeder cabinet is connected to the second DC charging screen; the second AC feeder cabinet is connected to the first DC charging screen.

In one of the embodiments, it also includes a communication power screen connected to communication equipment;

The first DC charging screen is respectively connected to the communication power supply screen through the first DC feeder screen and the first AC feeder cabinet;

The second DC charging screen is respectively connected to the communication power supply screen through the second DC feeder screen and the second AC feeder cabinet.

In one of the embodiments, the first AC uninterruptible power supply includes a first controller circuit, a first bypass circuit connected to the first controller circuit, and a first automatic switching device; wherein, the first bypass circuit is connected to the first AC switch cabinet; the first AC feeder cabinet and the first DC feeder screen are respectively connected to the first controller circuit through the first automatic switching device;

The second AC uninterruptible power supply includes a second controller circuit, a second bypass circuit connected to the second controller circuit, and a second automatic switching device; wherein, the second bypass circuit is connected to the second AC switch cabinet; the second AC feeder The cabinet and the second DC feeder screen are respectively connected to the second controller circuit through the second automatic switching device.

In one of the embodiments, the first DC charging panel includes a first single busbar and a second single busbar; the first DC feeder panel includes a first busbar section; wherein, the battery is connected to the first busbar section through the first single busbar; The first AC feeder cabinet and the second AC feeder cabinet are respectively connected to the first bus section through the second single bus;

The second DC charging panel includes the third single busbar and the fourth single busbar; the second DC feeder panel includes the second busbar section; wherein, the battery is connected to the second busbar section through the third single busbar; the first AC feeder cabinet, the second AC The feeder cabinets are respectively connected to the second bus section through the fourth single bus.

In one of the embodiments, the DC power supply system includes a contact appliance;

One end of the contact appliance is connected to the first bus section, and the other end is connected to the second bus section.

In one of the embodiments, the communication power panel includes a DC-DC module, an AC-DC module and a second automatic switching device;

The AC-DC module and the DC-DC module are respectively connected to the DC bus section of the communication power panel through the third automatic switching device;

The AC power system is connected to the AC-DC module; the DC power system is connected to the DC-DC module.

In one of the embodiments, the communication power panel further includes a DC circuit breaker;

One end of the DC circuit breaker is connected to the DC power system, and the other end is connected to the DC-DC module.

In one embodiment, the DC circuit breaker is a DC circuit breaker with a Type B tripping curve; the rated current of the DC circuit breaker with a Type B tripping curve is less than or equal to a quarter of the output current of the communication power supply panel.

One of the above technical solutions has the following advantages and beneficial effects:

The integrated AC and DC power supply system of the present invention simplifies the structure of the power supply equipment and realizes integrated monitoring by combining the AC uninterruptible power supply system, the AC power supply system and the DC power supply system into the AC and DC power supply integrated power supply system, and sharing the battery for power supply. The degree of automation of offshore wind farms is improved, and at the same time, automatic management and operation of the entire system can be carried out, effectively reducing the number and space of panel cabinets, and reducing commissioning workload and maintenance costs.

Description of drawings

Fig. 1 is the structural representation of an embodiment of the present invention being applied to land centralized control center;

Fig. 2 is a structural schematic diagram of an embodiment of the present invention applied to an offshore booster station;

Fig. 3 is a structural schematic diagram of a specific embodiment of the present invention applied to a centralized control center on land;

Fig. 4 is a structural schematic diagram of a specific embodiment of the present invention applied to an offshore booster station;

Fig. 5 is the schematic diagram of the circuit structure of the AC uninterruptible power supply system in a specific embodiment of the present invention;

6 is a schematic diagram of the circuit structure of a DC power supply system in a specific embodiment of the present invention;

Fig. 7 is a schematic diagram of the circuit structure of the communication power screen in a specific embodiment of the present invention.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the associated drawings. A preferred embodiment of the invention is shown in the drawings. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be thorough and complete.

It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to and integrally integrated with the other element, or there may be an intervening element at the same time. The terms "connected", "via" and similar expressions are used herein for the purpose of description only.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Description of an application scenario of the integrated AC and DC power supply system of the present invention:

The AC and DC power supply of offshore wind power generally adopts a decentralized design, independent configuration, and independent grouping of screens. 380V AC system, 220V DC system, AC uninterruptible power system (UPS: Uninterruptible Power System), inverter power supply, DC48V communication power system, etc., each subsystem adopts a decentralized design, and independent group screens are installed in different equipment rooms. The equipment consists of Different manufacturers produce, install and debug, and carry out maintenance and management according to different professional teams and maintenance personnel. Take an offshore wind farm project as an example: 65×4MW units are connected to a 220kV offshore booster station with a voltage of 35kV, and the layout Two 220/35kV main transformers with a capacity of 140MVA use two circuits of 220kV three-core 3×400mm2XLPE (Cross-linkedpolyethylene, cross-linked polyethylene) insulated submarine cables to transmit the power information of the offshore step-up station to the onshore centralized control center.

In view of the problem that the traditional technology cannot take into account the overall consideration of the power resources of the offshore wind farm, the embodiment of the present invention provides an embodiment 1 of an integrated AC and DC power supply system;

As shown in FIG. 1 , the integrated AC and DC power supply system of the embodiment of the present invention may include an AC power supply system 120, a DC power supply system 130 connected to a storage battery 100, and an AC uninterruptible power supply system 110 connected to the AC power equipment of an offshore wind farm;

One end of the DC power supply system 130 is connected to the AC uninterruptible power supply system 110 , and the other end is connected to the AC uninterruptible power supply system 110 through the AC power supply system 120 .

Specifically, in the embodiment of the present invention, the DC power supply system is directly connected to the battery, that is, it can directly supply power through the battery; one end of the DC power supply system can be directly connected to the AC uninterruptible power supply system to directly supply power for the AC uninterruptible power supply system. The other end of the power system can be connected to the AC UPS system through the AC power system, that is, the DC power system can supply power to the AC UPS system through the AC power system. The AC uninterruptible power supply system does not have a special battery, and adopts the host redundant configuration mode to supply power for important AC power equipment in the station, such as monitoring system, power collection system, navigation system, inverter power supply, etc., and used in offshore wind farms. The emergency lighting cabinets are arranged together in the secondary equipment room of the offshore step-up station or the onshore centralized control center. The embodiments of the present invention combine the AC uninterruptible power supply system, the AC power supply system, and the DC power supply system into an integrated AC and DC power supply system, share the battery power supply, simplify the structure of the power supply equipment, realize integrated monitoring, and improve the efficiency of offshore wind farms. At the same time, it can automatically manage and run the whole system, effectively reducing the number and space of screen cabinets, reducing the debugging workload and maintenance costs.

In one embodiment, as shown in FIG. 2 : the integrated AC and DC power supply system of the embodiment of the present invention may also include a communication power supply screen 240 connected to communication equipment;

One end of the communication power panel 240 is connected to the DC power system 230 , and the other end is connected to the DC power system 230 through the AC power system 220 .

Specifically, based on an application scenario of the embodiment of the present invention, in order to ensure the reliability of the communication power supply system, the offshore wind farm needs to be equipped with a dual communication power supply. The integrated AC and DC power supply system applied to the offshore booster station also includes a communication power supply panel, which is the communication power supply system configured for the offshore booster station. One end of the communication power supply panel is connected to the DC power supply system, and the other end is connected to the DC power supply through the AC power supply system. The system, that is, the communication power panel can be powered by the DC system in the station, which can effectively reduce the space of the offshore step-up station.

In one of the specific embodiments, as shown in Figure 3, the AC uninterruptible power supply system includes a first AC uninterruptible power supply (the first UPS) 332 and a second AC uninterruptible power supply (the second UPS) 334; the AC power supply system includes The first AC switch cabinet 314, the second AC switch cabinet 328, the first AC feeder cabinet 312 and the second AC feeder cabinet 316; the DC power supply system includes the first DC feeder panel 324, the second DC feeder panel 328, the first DC A current charging screen 322 and a second DC charging screen 326;

The first DC charging panel is respectively connected to the first AC uninterruptible power supply and the first AC feeder cabinet through the first DC feeder cabinet, and is respectively connected to the first AC uninterruptible power supply and the first AC switch cabinet through the first AC feeder cabinet; The two DC charging screens are respectively connected to the second AC uninterruptible power supply and the second AC feeder cabinet through the second DC feeder cabinet, and are respectively connected to the second AC uninterruptible power supply and the second AC switch cabinet through the second AC feeder cabinet. The first AC feeder cabinet is connected to the second DC charging screen; the second AC feeder cabinet is connected to the first DC charging screen.

Specifically, in the embodiment of the present invention, the AC uninterruptible power supply system includes a first AC uninterruptible power supply and a second AC uninterruptible power supply, and is also equipped with corresponding emergency lighting screens, that is, the first emergency lighting screen, the second emergency lighting screen screen; the AC uninterruptible power supply system supplies power for the AC load, the first AC uninterruptible power supply can supply power for the first emergency lighting screen, and the second AC uninterruptible power supply can supply power for the second emergency lighting screen. The AC uninterruptible power supply system can adopt the host redundant configuration mode to supply power for important AC power equipment in the station, such as monitoring system, power collection system, navigation system, inverter power supply, etc. The AC uninterruptible power supply system and 220V DC power supply system The storage battery system is connected, and there is no special storage battery. The AC uninterruptible power supply and emergency lighting screen are arranged in the secondary equipment room of the booster station.

The DC power supply system connected to the battery includes a first DC feeder panel, a second DC feeder panel, and a first DC charging panel and a second DC charging panel connected to each other; specifically, the voltage of the battery is 220V, and the DC power supply system is provided through the first The first DC charging screen and the second DC charging screen are respectively connected to the battery, and the 220V battery can directly supply power for the DC power system; the battery can be connected to the first AC uninterruptible power supply through the first DC charging screen and the first DC feeder screen in turn. , and the battery is connected to the second AC uninterruptible power supply through the second DC charging panel and the second DC feeder panel in turn, that is, the AC uninterruptible power supply and the DC power supply system share the battery.

The AC uninterruptible power supply system is not equipped with batteries, and when the AC power fails, it is powered by the DC power supply system. When the direct current - alternating current (DC/AC) module fails, transfer directly to the bypass output. In order to ensure the reliability of the system, the AC UPS system considers configuring the first AC UPS and the second AC UPS and adopts separate operation mode wiring, which can fully guarantee the reliability of the system.

Further, in the embodiment of the present invention, the DC power supply system can also be connected to the AC uninterruptible power supply system through the AC power supply system, and the AC power supply system includes a first AC switch cabinet, a second AC switch cabinet, and a first AC feeder cabinet connected to each other , the second AC feeder cabinet; the battery is connected to the first AC uninterruptible power supply through the first DC charging screen and the first AC feeder cabinet in turn, and the battery is connected to the second AC through the second DC charging screen and the second AC feeder cabinet in turn The uninterruptible power supply can effectively reduce the space of the offshore booster station and save the equipment of the battery.

In one of the specific embodiments, as shown in FIG. 4 , it also includes a communication power screen 440 connected to communication equipment; the first DC charging screen 422 is connected to the communication power supply screen 422 through the first DC feeder screen 424 and the first AC feeder cabinet 412 respectively. The power supply panel 440 and the second DC charging panel 426 are respectively connected to the communication power supply panel 440 through the second DC feeder panel 428 and the second AC feeder cabinet 416 .

Specifically, based on the application scenario of the embodiment of the present invention, the communication power panel in the integrated AC and DC power supply system is powered by the DC power supply system, as shown in Figure 4. It can be understood that the essence of the DC power supply system is that the battery is powered The system is connected to the communication power supply screen for power supply. On the one hand, the first DC charging screen is connected to the communication power supply screen through the first DC feeder cabinet, and the second DC charging screen is connected to the communication power screen through the second DC feeder cabinet. On the other hand, the first DC power supply screen The first AC feeder cabinet and the second DC charging panel are connected to the communication power supply panel through the second AC feeder cabinet, which can effectively ensure the reliability of the communication power supply.

In a specific embodiment, as shown in Figure 5, the first AC uninterruptible power supply includes a first controller circuit, a first bypass circuit connected to the first controller circuit, and a first automatic switching device; wherein, the first bypass circuit The circuit is connected to the first AC switch cabinet; the first AC feeder cabinet and the first DC feeder screen are respectively connected to the first controller circuit through the first automatic switching device;

The second AC uninterruptible power supply includes a second controller circuit, a second bypass circuit connected to the second controller circuit, and a second automatic switching device; wherein, the second bypass circuit is connected to the second AC switch cabinet; the second AC feeder The cabinet and the second DC feeder screen are respectively connected to the second controller circuit through the second automatic switching device.

Based on the application scenario of the embodiment of the present invention, the AC uninterruptible power supply system applied to the integrated AC and DC power supply system of the offshore step-up station or the land centralized control center includes a first AC uninterruptible power supply and a second AC uninterruptible power supply, That is to say, a dual-set redundant configuration mode can be adopted. Specifically, the capacity of the offshore step-up station is 220KV, and the storage battery is 220V. In the embodiment of the present invention, the AC uninterruptible power supply system is connected to the storage battery through the DC power supply system, and the first AC uninterruptible power supply is configured. (the first UPS), the second AC uninterruptible power supply (the second UPS), and the first emergency lighting screen and the second accident lighting screen are also configured. As shown in Figure 5, the first UPS and the first emergency lighting screen are the UPS power supply and the emergency lighting screen A in the figure, and the second UPS and the second accident lighting screen are the UPS power supply and the emergency lighting screen B in the figure. Specifically, in the UPS power supply and accident lighting A screen in Figure 5: the UPS bypass is the first bypass circuit, the automatic switching device is the first automatic switching device, and the controller circuit is the first controller circuit; In UPS power supply and emergency lighting B screen: UPS bypass is the second bypass circuit, the automatic switching device is the second automatic switching device, and the controller circuit is the second controller circuit;

The specific working process of dual-set redundant configuration is as follows:

When the output power of the first UPS and the second UPS is normal, the rectifier provides DC power to the inverters of the first UPS and the second UPS. At this time, the inverters of the first UPS and the second UPS are connected in parallel to share the load equally. 50% of current;

When the input power of the first UPS and the second UPS fails, the automatic switching device will switch the power supply to the inverter from the 220V storage battery, and the inverters of the first UPS and the second UPS will output in parallel, and the rated load current of each 50%;

When any one of the first UPS and the second UPS fails, the faulty UPS will automatically exit the parallel operation state, the static bypass switch of the faulty UPS will isolate the faulty UPS from the output bus, and the inverter of the normal UPS will continue to output. Bear all the load current, and the output process is completed automatically, without any disturbance to the load;

Furthermore, when any one of the UPSs fails, when the faulty UPS is overhauled, it is not necessary to switch to the manual maintenance bypass, and the power input, bypass input, internal DC battery switch, and output switch of the faulty UPS can be turned on. Internal inspection of the faulty UPS. At this time, the load is powered by the normal UPS; when the first UPS and the second UPS are out of operation due to a fault, the load can be powered by the static bypass power supply, and the time for the inverter to switch to the bypass power supply is less than 0.5ms, there is basically no disturbance to the load; when the first UPS and the second UPS have faults at the same time and need to be repaired, the operation can be transferred to the manual maintenance bypass, so that the bypass can supply power to the load, and then the faulty first UPS, the second UPS 2. Turn on the power input, bypass input, internal DC battery, and output switch of the UPS to realize the internal maintenance of the faulty UPS. At this time, the load is powered by the manual bypass.

It should be noted that in the embodiment of the present invention, the parameter description based on the application scenario: AC input voltage: 380V (85-115%), AC input frequency: 50HZ±5%, DC system input voltage: 220V: (80-115% %), ripple coefficient ≤5%, AC output voltage: 220V±2% (excluding AC direct input), AC output frequency: 50HZ±0.5% (excluding AC direct output).

The UPS load list of the offshore booster station is shown in Table 1:

Table 1 UPS load list of offshore booster station

According to the calculation method in Appendix C of the specification DL/T 5491-2014 "Technical Regulations for the Design of AC Uninterruptible Power Supply Systems in Electric Power Engineering", the calculation capacity of UPS is:

In the formula, S is the UPS calculation capacity (kVA), S _C is the calculation load (kVA), K _k is the reliability coefficient, which is 1.25, K _f is the power correction coefficient, which is 0.89, and K _d is the derating system, which is 1. Considering a certain redundant capacity, select the UPS capacity as 20kVA.

The current of the UPS is:

In the formula: S _C is the calculated load of the UPS; U is the voltage of the DC system, DC 220V; K _UPS is the load factor of the UPS of the wind farm, which is 0.5.

According to the specification DL/T 5491-2014, the offshore step-up substation is an unattended substation, and the UPS backup time can be 2 hours.

The UPS system is connected to the storage battery system of the 220V DC power supply system, and there is no dedicated storage battery. UPS power supply and emergency lighting cabinets are arranged in the secondary equipment room of the offshore booster station.

The UPS load list of the land centralized control center is shown in Table 2:

Table 2 UPS load list of onshore centralized control center

Similarly, according to the calculation method of the UPS capacity of the above-mentioned offshore step-up station, the calculation capacity of the UPS of the land centralized control center is 14kVA, the backup time is 2 hours, and its current value is 27.27A. The UPS system is connected to the storage battery system of the 220V DC power supply system, and there is no dedicated storage battery. The UPS power supply and emergency lighting cabinet are arranged in the relay room of the onshore centralized control center.

In a specific embodiment, as shown in Figure 6, the first DC charging panel includes a first single busbar and a second single busbar; the first DC feeder panel includes a first busbar section; wherein, the storage battery passes through the first single busbar Connect the first bus section; the first AC feeder cabinet and the second AC feeder cabinet are respectively connected to the first bus section through the second single bus;

The second DC charging panel includes the third single busbar and the fourth single busbar; the second DC feeder panel includes the second busbar section; wherein, the battery is connected to the second busbar section through the third single busbar; the first AC feeder cabinet, the second AC The feeder cabinets are respectively connected to the second bus section through the fourth single bus.

Specifically, the voltage of the DC power system in the embodiment of the present invention is 220V. According to the specification DL/T5491-2014, the offshore step-up station is an unattended substation, and the accident discharge time of the DC power system is 2 hours. At the same time, taking into account The reliability of the communication power supply, the accident discharge time of the communication power supply using the DC-DC module is 8 hours. Based on the above description, the DC power supply system in the embodiment of the present invention adopts single-bus connection, wherein the batteries connected to the first DC charging panel and the second DC charging panel are fixed valve-controlled sealed maintenance-free colloidal batteries for protection , control, anti-theft alarm, integrated automation equipment and other power supplies, the accident discharge time of the battery is 2 hours.

As shown in Figure 6, the storage battery and its charging device of the first DC charging panel and the storage battery and its charging device of the second DC charging panel are respectively connected to different bus sections, and the charging device is the first AC feeder cabinet (in the figure ^# 1 AC feeder cabinet) and the second AC feeder cabinet ( ^# 2 AC feeder cabinet in the figure), that is, the battery connected to the first DC charging panel ( ^# 1 DC charging panel in the figure) passes through the first single bus, and the charging device passes through The second single bus is connected to the first bus section corresponding to the first DC feeder panel ( ^# 1 DC feeder panel in the figure); the battery connected to the second DC charging panel ( ^# 2 DC charging panel in the figure) passes through the third single busbar , The charging device is connected to the second bus section corresponding to the second DC feeder panel ( ^# 2 DC feeder panel in the figure) through the fourth single busbar.

Preferably, the DC power supply system in the embodiment of the present invention includes a connecting appliance, one end of the connecting appliance is connected to the first bus section of the first DC feeder panel ( ^# 1 DC feeder panel in the figure), and the other end is connected to the second DC feeder panel ( ^# 2 DC feeder screen in the figure) for the second bus section. Specifically, the tie appliance can be used as a tie switch to connect the first DC feeder panel and the bus section of the second DC feeder panel. When the wiring is normal and the charging device can charge normally in the DC power system respectively, the contact switch is in the normally open state; when the charging device fails to charge in the first DC charging screen or the second DC charging screen, the contact switch is closed, The first DC feeder panel is connected to the bus section of the second DC feeder panel, and the battery connected to the first DC charging panel can supply power for the second DC charging panel. The current charging screen is powered, which effectively solves the problem that the circuit failure affects the normal operation of the system, and at the same time saves power resources.

It should be noted that, in the embodiment of the present invention, the parameter description based on the application scenario:

In the DC power system of the integrated AC and DC power supply system of the offshore step-up station, according to the requirements of the DL/T5044-2014 specification, the discharge termination voltage is 1.87V, and the reliability factor _K is 1.4. According to the calculation method of UPS capacity, the battery capacity is calculated as 519.99Ah, considering a certain redundant capacity, so the battery capacity is selected as 600Ah. According to the method of the embodiment of the present invention, a 20A high-frequency switching power supply module is selected, and the charging module is configured according to (N+1), and six 20A high-frequency switching power supply modules can be used to connect to the charging device. The battery is arranged in the battery room of the offshore booster station, and the first DC charging panel, the second DC charging panel, the first DC feeder panel and the second DC feeder panel are arranged in the secondary equipment room of the offshore booster station. The embodiment of the present invention effectively saves the space of the offshore booster station. It can save 2 UPS bypass cabinets, 2 UPS feeder cabinets, 2 communication power feeder cabinets and other screen cabinets. At the same time, save 2 sets of communication power battery

In the DC power supply system of the integrated AC and DC power supply system of the centralized control center on land, according to the requirements of the DL/T5044-2014 specification, the battery capacity is calculated according to the ladder calculation method, and the calculated battery capacity is 394.46Ah. Considering a certain redundant capacity, Therefore, the battery capacity is selected as 400Ah. Based on the battery capacity, four 20A high-frequency switching power supply modules can be used to connect to the charging device. The battery is arranged in the battery room of the onshore centralized control center, and the first DC charging panel, the second DC charging panel, the first DC feeder panel and the second DC feeder panel are arranged in the secondary equipment room of the onshore centralized control center. The embodiment of the present invention effectively saves the space of the centralized control center on land, simplifies the power supply system, and can save 2 UPS bypass cabinets, 2 UPS feeder cabinets and other screen cabinets.

In one of the embodiments, as shown in Figure 7, the communication power panel includes a DC-DC module, an AC-DC module, and a second automatic switching device; the AC-DC module and the DC-DC module are respectively connected through the third automatic switching device The DC bus section of the communication power panel; the AC power system is connected to the AC-DC module; the DC power system is connected to the DC-DC module.

Specifically, the embodiment of the present invention is applied to the AC-DC integrated power system of the offshore step-up station. The communication power panel is powered by the DC power system in the station. According to the specification DL/T 5491-2014, based on the DC load statistics of communication equipment, The DC/DC load is obtained to be 3.65kW. The load factor of the DC/DC module is 0.8, and the current of the DC/DC module is 13.27A according to the above UPS current calculation method. In order to ensure the reliability of the communication power supply, the discharge time of the DC/DC module of the communication power supply panel is 8 hours, and a set of AC-DC corresponding to the DC-DC (DC/DC) module can be added to the busbar in the communication power supply panel. (AC/DC) module output, the DC power system can be connected to the communication power supply panel in two ways, that is, each bus in the communication power supply panel can have 2 sets of AC/DC module output.

Specifically as shown in Figure 7, the four switching devices in the figure are the third automatic switching device in the embodiment of the present invention, and the first AC feeder cabinet ( ^# 1 AC feeder cabinet in the figure) is connected to the third automatic switching device through the AC/DC module. The first end of the switching device, the first DC feeder screen ( ^# 1 DC feeder screen in the figure) is connected to the first end of the third automatic switching device through the DC/DC module, and the second end of the third automatic switching device is connected to the communication On the busbar of the power supply panel; similarly, the second AC feeder cabinet ( ^# 2 AC feeder cabinet in the figure) is connected to the first end of the automatic switching device through the AC/DC module, and the second DC feeder panel ( ^# 2 DC feeder panel in the figure) The first end of the automatic switching device is connected through the DC/DC module, and the second end of the third automatic switching device is connected to the bus bar of the communication power supply panel. The bus bar of the connected communication power supply panel is the same section of DC 48V bus bar. When the system supplies power to the communication equipment normally, the DC/DC module provides power output. When the DC fault or the DC/DC module fails, it can automatically switch to the AC/DC module in zero milliseconds, effectively improving the working efficiency of the system and ensuring reliability of the system power supply.

In order to ensure the reliability of the communication power supply, the wind farm can be equipped with dual communication power supply. The onshore communication DC part is equipped with an independent communication machine room and communication DC battery room, and the AC and DC integrated system applied to the land centralized control center does not include the communication power supply panel and the corresponding battery.

In a specific embodiment, the communication power panel further includes a DC circuit breaker;

One end of the DC circuit breaker is connected to the DC power system, and the other end is connected to the DC-DC module.

Preferably, the DC circuit breaker is a DC circuit breaker with a Type B tripping curve; the rated current of the DC circuit breaker with a Type B tripping curve is less than or equal to a quarter of the output current of the communication power supply panel.

Specifically, when there is a large current overload impact on the communication load or a short-circuit fault occurs in the feeder circuit, the output current limiting protection action of the DC/DC module may cause the bus voltage to drop and the communication equipment to lose power. For the integrated system of AC and DC power supply in offshore wind farms, it can operate reliably through the cooperation of circuit breakers.

The total output current of the DC/DC module should not be less than 4 times the rated current of the largest DC circuit breaker in the feeder circuit to ensure that the overcurrent protection of the feeder switch can operate. The instantaneous tripping range of B-type micro-break is 4In~7In, which is suitable for protecting loads with small short-circuit current. The DC circuit breaker with B-type tripping curve should be selected as the feeder circuit breaker to reduce the tripping action value of the circuit breaker.

The embodiment of the present invention simplifies the structure of the power supply equipment of the offshore wind farm, so that the reliability, availability and maintainability of the station power supply are improved, and at the same time, the investment cost of the offshore booster station is effectively saved. In practical engineering applications, it also has its special advantages, including: all equipment is in charge of the only supplier, ensuring the size and size consistency of all cabinets, effectively reducing the number and space of screen cabinets, reducing debugging workload and Maintenance costs; integrated monitoring improves the automation of offshore wind farms. It can carry out automatic management and operation for the whole system, control the output voltage and current of each feeding system, timely and accurately judge the abnormality or fault type, and automatically realize functions such as fault protection and sound and light alarm display.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. An integrated AC and DC power supply system, characterized in that it includes: an AC power supply system, a DC power supply system connected to a storage battery, and an AC uninterruptible power supply system connected to the AC power equipment of an offshore wind farm; One end of the DC power supply system is connected to the AC uninterruptible power supply system, and the other end is connected to the AC uninterruptible power supply system through the AC power supply system. 2. The integrated AC and DC power supply system according to claim 1, further comprising a communication power panel connected to communication equipment; One end of the communication power panel is connected to the DC power system, and the other end is connected to the DC power system through the AC power system. 3. The integrated AC and DC power supply system according to claim 1, wherein the AC uninterruptible power supply system includes a first AC uninterruptible power supply and a second AC uninterruptible power supply; the AC power supply system includes a first AC switch cabinet, second AC switch cabinet, first AC feeder cabinet and second AC feeder cabinet; the DC power supply system includes a first DC feeder screen, a second DC feeder screen, a first DC charging screen and a second DC charging screen; The first DC charging panel is respectively connected to the first AC uninterruptible power supply and the first AC feeder cabinet through the first DC feeder cabinet, and is respectively connected to the first AC uninterruptible power supply, the first AC switch cabinet; The second DC charging panel is respectively connected to the second AC uninterruptible power supply and the second AC feeder cabinet through the second DC feeder cabinet, and is respectively connected to the second AC uninterruptible power supply through the second AC feeder cabinet. Intermittent power supply, the second AC switch cabinet. The first AC feeder cabinet is connected to the second DC charging panel; the second AC feeder cabinet is connected to the first DC charging panel. 4. The integrated AC and DC power supply system according to claim 3, further comprising a communication power panel connected to communication equipment; The first DC charging screen is respectively connected to the communication power supply screen through the first DC feeder screen and the first AC feeder cabinet; The second DC charging panel is connected to the communication power supply panel through the second DC feeder panel and the second AC feeder cabinet respectively. 5. The integrated AC and DC power supply system according to any one of claims 3 or 4, wherein the first AC uninterruptible power supply includes a first controller circuit and a second controller circuit connected to the first controller circuit A bypass circuit and a first automatic switching device; wherein, the first bypass circuit is connected to the first AC switch cabinet; the first AC feeder cabinet and the first DC feeder screen pass through the first an automatic switching device connected to the first controller circuit; The second AC uninterruptible power supply includes a second controller circuit, a second bypass circuit connected to the second controller circuit, and a second automatic switching device; wherein, the second bypass circuit is connected to the second An AC switch cabinet; the second AC feeder cabinet and the second DC feeder screen are respectively connected to the second controller circuit through the second automatic switching device. 6. The integrated AC and DC power supply system according to any one of claims 3 or 4, wherein the first DC charging panel includes a first single busbar and a second single busbar; the first DC The feeder panel includes a first bus section; wherein, the storage battery is connected to the first bus section through the first single bus; the first AC feeder cabinet and the second AC feeder cabinet are respectively connected through the second single a busbar connecting said busbar sections; The second DC charging panel includes a third single busbar and a fourth single busbar; the second DC feeder panel includes a second busbar section; wherein, the storage battery is connected to the second busbar section through the third single busbar ; The first AC feeder cabinet and the second AC feeder cabinet are respectively connected to the second bus section through the fourth single busbar. 7. The integrated AC and DC power supply system according to claim 6, characterized in that, the DC power supply system includes contact appliances; One end of the connecting device is connected to the first bus section, and the other end is connected to the second bus section. 8. The integrated AC and DC power supply system according to claim 2, wherein the communication power panel includes a DC-DC module, an AC-DC module and a third automatic switching device; The AC-DC module and the DC-DC module are respectively connected to the DC bus section of the communication power panel through the third automatic switching device; The AC power system is connected to the AC-DC module; the DC power system is connected to the DC-DC module. 9. The integrated AC and DC power supply system according to claim 8, wherein the communication power panel further includes a DC circuit breaker; One end of the DC circuit breaker is connected to the DC power system, and the other end is connected to the DC-DC module. 10. The integrated AC and DC power supply system according to claim 9, wherein the DC circuit breaker is a DC circuit breaker with a B-type tripping curve; The rated current of the DC circuit breaker of the type B tripping curve is less than or equal to a quarter of the output current of the communication power supply panel.