CN204046193U - A kind of mixed type micro-grid system - Google Patents

Abstract

The utility model discloses a hybrid micro-grid system, which comprises a micro-grid parent network, a renewable energy power generation system, an AC load, and a power transmission and distribution line. On the distribution line, wherein: the microgrid parent network further includes one or more auxiliary branches, and each auxiliary branch includes an auxiliary power supply system, a bidirectional converter and a first battery unit; in each auxiliary branch, the auxiliary The AC output from the power supply system is delivered to the first AC end of the bidirectional converter, the second AC end of the bidirectional converter is connected to the power transmission and distribution line, and the first battery unit is connected to the battery terminal of the bidirectional converter. The beneficial effect of implementing the utility model is that photovoltaic and wind power generation are used as the main energy sources to provide electric energy to the load and store excess energy in the battery unit. When the supply of renewable energy and battery energy storage is insufficient, the auxiliary power supply system Provide power supply.

Description

A Hybrid Microgrid System

technical field

The utility model relates to the technical field of micro-grids, in particular to a hybrid micro-grid system.

Background technique

At present, in order to solve the problem of electricity consumption in Northwest China and offshore islands, the National Energy Administration usually uses diesel engines for power supply. However, the use of diesel engines for power supply has serious environmental pollution, poor power supply quality, low energy efficiency utilization, and inconvenient diesel transportation in remote areas and island areas. It is often affected by the weather, diesel supply is not timely, and power outages often occur.

With the further implementation of the national "Twelfth Five-Year Plan", photovoltaic power generation, as a major new energy source, is being widely used, but for new energy represented by photovoltaic power generation to be connected to the diesel engine grid, the operation of the grid will be very unstable, and Control is complicated.

Utility model content

The technical problem to be solved by the utility model is to provide a hybrid micro-grid system for the defect of the prior art that the new energy represented by photovoltaic power generation is connected to the diesel engine grid, resulting in very unstable grid operation.

The technical solution adopted by the utility model to solve the technical problem is: to construct a hybrid microgrid system, including a microgrid parent network, a renewable energy power generation system, an AC load and power transmission and distribution lines, the microgrid parent network, Renewable energy generation systems and AC loads are respectively connected to the transmission and distribution lines, wherein: the microgrid parent network further includes one or more auxiliary branches, and each of the auxiliary branches includes an auxiliary power supply system, a bidirectional converter and a first battery unit; in each auxiliary branch, the alternating current output from the auxiliary power supply system is sent to the first alternating current terminal of the bidirectional converter, and the second alternating current terminal of the bidirectional converter is connected to the The power transmission and distribution line is connected, and the first battery unit is connected to the battery terminal of the bidirectional converter.

In the above hybrid microgrid system, the hybrid microgrid system further includes an energy storage converter and a second battery unit, wherein: the DC terminal of the energy storage converter is connected to the second battery unit, The AC end of the energy storage converter is connected to the power transmission and distribution line.

In the above hybrid micro-grid system, the auxiliary power supply system is a power grid/diesel generator system/gas generator system.

In the above-mentioned hybrid micro-grid system, the renewable energy power generation system includes a renewable energy power generation module and an inverter, wherein: the direct current output by the renewable energy power generation module is delivered to the output power through the inverter on the distribution line.

In the above hybrid micro-grid system, the renewable energy generation module is photovoltaic power generation/wind power generation.

In the above hybrid microgrid system, the hybrid microgrid system also includes at least one expansion subnetwork unit, each expansion subnetwork unit is respectively connected to the transmission and distribution lines, and each expansion subnetwork unit includes a or a plurality of expansion subnets connected in series, wherein: each expansion subnet further includes:

Subnet bidirectional converter;

The first battery unit of the subnetwork, the first battery unit of the subnetwork is connected to the battery terminal of the bidirectional converter of the subnetwork;

A subnetwork AC load, the subnetwork AC load is connected to the AC output end of the subnetwork bidirectional converter;

A sub-network renewable energy power generation system, the sub-network renewable energy power generation system is respectively connected to the AC output end of the sub-network bidirectional converter and the sub-network AC load.

In the above-mentioned hybrid microgrid system, each expansion sub-network also includes: a sub-network energy storage converter and a second battery unit of the sub-network, and in each expansion sub-network, the sub-network energy storage converter The AC terminal of the subnetwork is connected to the AC output terminal of the bidirectional converter of the subnetwork, and the DC terminal of the energy storage converter of the subnetwork is connected to the second battery unit of the subnetwork.

The hybrid micro-grid system implementing the utility model has the following beneficial effects: based on the bidirectional converter, the power grid or diesel generator system, gas generator system as the source power, photovoltaic power generation or wind power generation and energy storage by the first battery unit The inverter is the main form of new energy, which solves the problems of micro-grid applications such as the access of new energy such as photovoltaic power generation, the access of diesel generator systems (standby), and the stability of power supply. It can be applied to various areas without electricity, small hydropower Power supply areas for power generation and diesel generators meet the basic electricity consumption of people in areas without large power grids in Northwest China and island areas, and improve people's quality of life.

Description of drawings

The utility model will be further described below in conjunction with accompanying drawing and embodiment, in the accompanying drawing:

Fig. 1 is the schematic diagram of the utility model hybrid microgrid system embodiment;

Figure 2 is the energy flow diagram of the hybrid microgrid system with the bidirectional converter as the core;

FIG. 3 is a schematic diagram of multi-level expansion based on FIG. 1 .

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the utility model, the specific implementation of the utility model is described in detail with reference to the accompanying drawings.

As shown in Figure 1, it is a schematic diagram of an embodiment of the hybrid microgrid system of the present invention. The hybrid microgrid system uses renewable energy power generation systems such as photovoltaic power generation, wind power generation, etc. as the main power supply system, and the power grid/diesel generator The system/gas generator system is a backup power supply system, combined with battery unit energy storage technology, which meets the basic electricity consumption of people in areas without large power grids in Northwest China and island areas, and improves people's quality of life. Specifically, the hybrid microgrid system includes a microgrid parent network 10, a renewable energy generation system 20, an AC load 30, and a power transmission and distribution line 40, wherein: the microgrid parent network 10, the renewable energy generation system 20, the AC load 30 are connected to the power transmission and distribution lines 40 respectively. In particular, the microgrid parent grid 10 further includes one or more auxiliary branches 100 , and each auxiliary branch 100 includes an auxiliary power supply system 101 , a bidirectional converter 102 and a first battery unit 103 .

In this embodiment, the auxiliary power supply system is preferably a power grid/diesel generator system or a gas generator system. The AC power output by the auxiliary power supply system 101 is delivered to the first AC end of the bidirectional converter 102 of the auxiliary branch where the two-way The second AC end of the converter 102 is connected to the power transmission and distribution line 40 , and its battery end is connected to the first battery unit 103 of the auxiliary branch. All the first battery units 103 form a battery pack. The bidirectional converter 102 converts the AC power output by the power grid/diesel generator system/gas generator system into DC power and stores it in the first battery unit 103. At the same time, the bidirectional converter 102 converts the DC power into AC power and transmits it to the power transmission and distribution line 40 It is used for AC load 30 above. The above-mentioned renewable energy power generation system 20 includes a renewable energy power generation module 201 and an inverter 202. In this embodiment, the renewable energy power generation module 201 is preferably photovoltaic power generation/wind power generation, and the DC power output by it is reversed by the inverter 202. After being converted into alternating current, it is sent to the power transmission and distribution line 40 for use by the alternating current load 30 .

The above-mentioned hybrid microgrid system also includes an energy storage converter 50 and a second battery unit 60, wherein: the DC terminal of the energy storage converter 50 is connected to the second battery unit 60, and the AC terminal of the energy storage converter 50 is connected to the second battery unit 60. The power transmission and distribution line 40 is connected. In this embodiment, the energy storage converter 50 is used as a PQ source to cooperate with energy storage.

In this embodiment, the bidirectional converter adopts the IBD100 series bidirectional converter, the first AC end of which is connected to the power grid/diesel generator system and the gas generator system, and the energy storage converter adopts the IES100 series energy storage converter. As a PQ source with energy storage, the renewable energy power generation system uses commonly used photovoltaic power generation, wind power generation, etc. to provide new energy. The hybrid microgrid system of the utility model is based on the bidirectional converter, which is the most important energy flow control device, as shown in Figure 2, which is the energy flow diagram of the microgrid system with the bidirectional converter as the core. The converters each include a bidirectional rectifier 11 and a bidirectional inverter 12, the DC output terminals of the bidirectional rectifier 11 and the DC input terminals of the bidirectional inverter 12 are respectively connected to the DC bus 13, and the DC bus 13 is connected to the first battery unit 103 , the leading line of the AC input end of the bidirectional rectifier 11 is the first AC bus 14 , and the leading line of the AC output end of the bidirectional inverter is the second AC bus 15 .

As the main energy flow controller in the hybrid microgrid system, the bidirectional converter above performs AC/DC conversion on the alternating current on the first AC bus 14 through the bidirectional rectifier 11, and then uses the bidirectional inverter 12 to convert the bidirectional rectifier 11 or The DC power supplied by the first battery unit 103 is coupled to the second AC bus bar 15 after DC/AC conversion, so as to realize the first AC bus bar and the first battery unit, the first battery unit and the second AC bus bar, and the first AC bus bar and the second AC bus bar. Bi-directional controllable flow of energy between AC buses. Its energy flow working mode is as follows:

When the power supply of the first AC bus 14 is normal, that is, the power grid or the diesel generator system or the gas generator system provides the first AC bus power supply, the bidirectional rectifier 11 performs AC/DC conversion on the power supply on the first AC bus 14, Supply power to the first battery unit 103 and the bidirectional inverter 12, and the bidirectional inverter converts the direct current to DC/AC to provide electric energy for the second AC bus 15 (equivalently connected to the power transmission and distribution line 40 in FIG. 1 ), At the same time, the energy storage converter 50 obtains a system command (the command includes a constant value of input power), and stores energy through intelligent constant power control (that is, realizes constant power input), as shown in broken line 1 in the figure. In addition, when the energy of the first battery unit is sufficient, the energy of the first battery unit can be injected into the first AC bus 14 through the bidirectional rectifier 11 through intelligent constant power control, so as to provide AC loads connected to the first AC bus 14. Energy, see broken line 2 in the figure. When the AC load connected to the second AC bus 15 (take the AC load 30 connected to the transmission and distribution line 40 in Fig. 1 as an example) needs energy, the energy storage converter can also be controlled by intelligent constant power according to the system instruction The energy is fed to the second AC bus 15, and at the same time, the bidirectional converter can also feed excess energy to the first AC bus 14, as shown by the broken line 3 in the figure.

When the power supply of the first AC bus 14 is abnormal, that is, when the power grid or the diesel generator system or the gas generator system is not working or is working abnormally, the first AC bus 14 of the bidirectional converter does not supply power, and its bidirectional rectifier 11 automatically stops, and the bidirectional inverter The converter 12 uses the energy of the first battery unit to continue to provide energy for the second AC bus 15 , and the energy storage converter provides electric energy for the second AC bus 15 through system instructions, as shown in broken line 4 in the figure.

As shown in Figure 3, based on the hybrid microgrid system in Figure 1, multiple independent subnetworks can be constructed through multi-level expansion to provide power for AC loads with different security levels. Specifically, the hybrid microgrid system also includes at least one expansion subnetwork unit (not shown in the figure), each expansion subnetwork unit is connected to the power transmission and distribution line 40, and each expansion subnetwork unit includes one or more The capacity expansion subnetwork 70 that is connected in series, in this embodiment, take including two capacity expansion subnetwork units as example, the first capacity expansion subnetwork unit comprises a capacity expansion subnetwork 70, and the second capacity expansion subnetwork unit comprises three capacity expansion subnetwork units The expansion subnets 70 connected in series, as shown in the figure, each expansion subnet 70 further includes: a subnet bidirectional converter 701, the AC input end of the subnet bidirectional converter 701 and the power transmission and distribution line 40/last expansion The AC output end of the subnet bidirectional converter of the subnet is connected; the first battery unit 702 of the subnet, the first battery unit 702 of the subnet is connected with the storage battery end of the subnet bidirectional converter 701; the subnet AC load 703, the subnet AC The load 703 is connected to the AC output end of the subnetwork bidirectional converter 701; the subnetwork renewable energy power generation system 704, and the subnetwork renewable energy power generation system 704 is respectively connected to the AC output terminal of the subnetwork bidirectional converter and the subnetwork AC load.

The above-mentioned subnetwork bidirectional converter 701 in the expansion subnetwork connected to the transmission and distribution line 40 obtains electric energy from the power transmission and distribution line 40, stores energy for the first battery unit 702 of the subnetwork through the subnetwork bidirectional converter 701, and simultaneously supplies energy to the subnetwork. grid AC load power supply, the sub-network renewable energy generation system 704 also includes a sub-network renewable energy generation module and a sub-network inverter, the sub-network renewable energy generation module is preferably photovoltaic power generation/wind power generation, and the DC power generated by it passes through the sub-network The inverter supplies power to the AC loads of the sub-network. Preferably, each expansion sub-network also includes a sub-network energy storage converter 705 and a second sub-network battery unit 706. The sub-network energy storage converter 705 is used as a PQ source to cooperate with energy storage, and the AC power is converted into DC power and stored in the subnetwork in the second battery unit 706 .

In the hybrid microgrid system of the utility model, based on the bidirectional converter, the power grid or diesel engine power generation system, gas generator system as the source power, photovoltaic power generation or wind power generation and the energy storage and inversion of the first battery unit are the main new energy sources. It solves the problems of micro-grid applications such as the access of new energy sources such as photovoltaic power generation, diesel generator system access (standby), and power supply stability. It can be applied to various areas without electricity, including diesel power generation and small hydropower generation. The power supply can be directly connected to realize the hybrid off-grid micro-grid topology with renewable energy as the main form of power supply.

Implementation of the utility model hybrid micro-grid system, its beneficial effects are as follows:

1) The power transmission and distribution lines are built with converter equipment designed by modern power electronics technology, which solves the problems of poor power quality and unstable power supply of diesel engines;

2) Combined with the energy storage technology of the battery unit, it solves the problem of excess electric energy storage when new energy sources such as photovoltaic power generation are connected;

3) Support diesel engine access, as a backup power supply, when new energy sources such as photovoltaic power generation are not enough, backup power supply is provided to ensure continuous power generation of the microgrid system;

4) The diesel generator system is used as a backup power supply. When the electric energy provided by photovoltaic power generation or wind power generation and the electric energy stored in the battery unit are sufficient, the power supply cost and environmental pollution can be greatly reduced without turning on the diesel engine.

Embodiments of the present utility model have been described above in conjunction with the accompanying drawings, but the present utility model is not limited to the above-mentioned specific implementation, and the above-mentioned specific implementation is only illustrative, rather than restrictive. Under the enlightenment of the utility model, personnel can also make many forms without departing from the scope of protection of the purpose of the utility model and claims, and these all belong to the protection of the utility model.

Claims (7)

1. A hybrid micro-grid system, characterized in that it comprises a micro-grid parent network, a renewable energy generation system, an AC load, and a power transmission and distribution line, and the micro-grid parent network, a renewable energy generation system and an AC load are respectively Connected to the transmission and distribution line, wherein: the microgrid parent network further includes one or more auxiliary branches, and each of the auxiliary branches includes an auxiliary power supply system, a bidirectional converter and a first battery unit; In each auxiliary branch, the AC power output by the auxiliary power supply system is sent to the first AC end of the bidirectional converter, and the second AC end of the bidirectional converter is connected to the power transmission and distribution line, the The first battery unit is connected to the battery terminal of the bidirectional converter. 2. The hybrid microgrid system according to claim 1, wherein the hybrid microgrid system further comprises an energy storage converter and a second battery unit, wherein: the DC power of the energy storage converter The terminal is connected to the second battery unit, and the AC terminal of the energy storage converter is connected to the power transmission and distribution line. 3. The hybrid microgrid system according to claim 1, wherein the auxiliary power supply system is a power grid/diesel generator system/gas generator system. 4. The hybrid micro-grid system according to claim 1, wherein the renewable energy power generation system includes a renewable energy power generation module and an inverter, wherein: the direct current output by the renewable energy power generation module is passed through The inverter is delivered to the power transmission and distribution line. 5. The hybrid micro-grid system according to claim 4, wherein the renewable energy generation module is photovoltaic power generation/wind power generation. 6. The hybrid microgrid system according to claim 1, wherein the hybrid microgrid system also includes at least one expansion subnetwork unit, and each expansion subnetwork unit is connected to the transmission and distribution line respectively , and each expansion subnet unit includes one or more expansion subnets connected in series, wherein: each expansion subnet further includes: Subnet bidirectional converter; The first battery unit of the subnetwork, the first battery unit of the subnetwork is connected to the battery terminal of the bidirectional converter of the subnetwork; A subnetwork AC load, the subnetwork AC load is connected to the AC output end of the subnetwork bidirectional converter; A sub-network renewable energy power generation system, the sub-network renewable energy power generation system is respectively connected to the AC output end of the sub-network bidirectional converter and the sub-network AC load. 7. The hybrid microgrid system according to claim 6, wherein each expansion subnet further comprises: a subnet energy storage converter and a second battery unit of the subnet, and in each expansion subnet , the AC end of the sub-network energy storage converter is connected to the AC output end of the sub-network bidirectional converter, and the DC end of the sub-network energy storage converter is connected to the second battery unit of the sub-network.