KR101946632B1 - Microgrid system based on small hydro power - Google Patents

Abstract

The present invention relates to a microgrid system based on small hydroelectric power generation and includes a distributed power unit, an energy storage unit, a user load unit, a DC grid unit, and an energy control unit. The distributed power unit generates power Power generation can be eco-friendly, stable power supply and management can be achieved, and power utilization efficiency can be improved.

Description

Microgrid system based on small hydro power generation

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply system using renewable energy, and more particularly to a micro grid system based on small hydro power using small hydro power.

In order to solve various problems of conventional power generation facilities such as thermal power generation, many electric power supply systems using renewable energy such as wind power, solar power, and tidal power have been developed. Thus, demand power and supply power in a small power supply source Microgrid systems are also being actively developed.

According to Korean Patent No. 10-1212343, as an example of a conventional micro grid system using renewable energy, an internal environmental information monitoring unit, an external environment information receiving unit, a power usage predicting unit, and a power control unit are included, And a microgrid operating system that allows commercial power to be efficiently and intelligently managed. As another example, Korean Patent No. 10-1412742 discloses a power generation system having a diesel generator, a renewable energy power source and an energy storage device, and an energy management system (EMS) and a power management system (PMS) A stand-alone microgrid control system with improved stability is disclosed.

However, since such a conventional micro grid system uses sunlight as a main renewable energy source, there is a problem that the output fluctuation is large and the dependence on the diesel generator becomes high. Therefore, it is necessary to develop a micro grid system focusing on new and renewable energy sources that have less fluctuation of power generation than sunlight and are easy to predict.

On the other hand, in recent years, a small amount of carbon dioxide (CO2) is a clean energy source, and the energy density is high, so a lot of small hydro power generation is being studied. Micro power generation (100kw or less) and pico-class (5kw or less) are being developed in the range where clean energy can be developed as a power supply system in which water turbine is rotated by gravity of water and used as power generation power.

However, most of the electric power supply systems using small hydrogens as energy sources are installed only as stand-alone systems, which is inefficient because they can not sufficiently utilize electric power generated for 24 hours. Therefore, there is a high need to develop a micro-grease system based on a small hydrograph associated with the system.

Korean Patent No. 10-1212343 Korean Patent No. 10-1412742

An object of the present invention is to solve the above-described problems in the conventional micro grid system, and it is an object of the present invention to provide a small-scale power generation system capable of generating power environmentally, stably supplying and managing power, To provide a microgrid system based on the microgrid system.

According to an aspect of the present invention, there is provided a microgrid system based on small hydrographic power generation, comprising: a distributed power source unit generating power from a plurality of energy sources; An energy storage unit for storing and managing electric power by charging / discharging electric power generated in the distributed power unit to / from a battery; A system power supply for generating system power; A user load unit that consumes power generated by the distributed power unit and the grid power unit; A DC grid unit for converting an input voltage from the distributed power source unit, an energy storage unit, and a grid power source unit to a common DC voltage, converting an output voltage to the user load unit to an AC voltage, and distributing power; And an energy controller for monitoring the states of the distributed power unit, the energy storage unit, the grid power unit, the user load unit, and the DC grid unit, and controlling each operation according to the monitoring result.

Preferably, the distributed power unit includes a small hydroelectric power generator that generates electric power using a small hydrostatic power.

The energy control unit compares the small amount of power generated by the small hydropower generator with the load usage of the user load unit, monitors the charge state of the energy storage unit,

a) supplying the small-capacity power to the user load section when the small-hydro-power amount is equal to the load usage amount,

b) if the small hydraulic power amount is smaller than the load usage amount and the charging state of the energy storage unit is equal to or higher than a predetermined level, charging the user load unit with the charging power of the energy storage unit together with the small-

c) supplying the grid power of the grid power unit to the user load unit together with the small-hydro power when the small-hydropower power amount is smaller than the load usage amount and the charging state of the energy storage unit is less than a predetermined level,

d) supplying the small-capacity power to the user load unit and charging the energy storage unit when the small-hydroelectric power amount is larger than the load usage amount and the charging state of the energy storage unit is not full,

and e) the power generation amount of the small hydropower generator is controlled so that the small hydraulic power amount is equal to the load usage amount when the small hydraulic power amount is larger than the load usage amount and the charged state of the energy storage part is full.

Preferably, the energy control unit monitors the flow state and the output power state of the small hydropower generator and controls the output power of the small hydropower generator by controlling the flow rate or the flow velocity of the flow path according to the monitoring result.

In addition, the small hydrostatic power generator may further include a bypass flow path for regulating a flow rate or a flow rate.

Further, the small hydrostatic power generator includes a plurality of flow rate or flow rate sensors for controlling the flow rate or flow rate of the incoming gas, and it is possible to judge the flow rate or the flow rate value of the flow passage according to the following formula based on the measured value from the flow rate or flow rate sensor desirable.

,

,

F: Determined value of flow rate or flow rate

F _n : measured value of nth sensor

N; Number of installed sensors

k _n : Weight according to the distance of the nth sensor

The DC grid unit may include an AC-DC converter for converting an AC voltage of the small hydro-electric generator into a DC voltage; A DC-DC converter for boosting and reducing the DC voltage of the energy storage unit; An inverter / rectifier for converting an output voltage of the AC-DC converter and the DC-DC converter to an AC voltage and supplying the AC voltage to the user load unit, and rectifying the AC voltage of the grid power unit to a DC voltage; And a DC bus connecting the outputs of the AC-DC converter, the DC-DC converter, and the inverter / rectifier.

Preferably, the system power supply unit is a diesel generator that generates electricity using a diesel engine, the distributed power unit includes a solar power generator that generates power using solar light; And a wind power generator that generates power using wind power, and the small hydro power generator is preferably a small hydro power generator to which pelton aberration is applied.

The microgrid system based on the small hydroelectric power generation of the present invention has the following advantageous effects.

First, by using small-scale hydroelectric power generation which is eco-friendly and small fluctuation of output power as a main power supply source, stable power can be supplied to a large number of users while reducing environmental pollution.

Second, the power generation equipment cost is low and the operation time of the diesel generator is reduced as compared with the system including only the conventional solar power generator, so that the economical efficiency is high.

Third, integrated control of multiple distributed power sources makes it possible to manage power supply easily and real-time maintenance of each generator.

Fourthly, a plurality of flow rate or flow rate sensors are installed in the flow path of the small hydro-electric power generator, the measured value of the flow rate or flow rate is given a weight value to obtain a correct flow rate or flow rate value, The error value of the sensor can be lowered and the turbine can be safely protected from over-rotation or over-voltage.

Fifth, it can be used in conjunction with grid power, and it is possible to generate power for 24 hours by small-scale hydroelectric power generation, so that utilization of energy storage system is high.

1 is a block diagram conceptually illustrating a micro grid system according to an embodiment of the present invention.
FIG. 2 is a block diagram showing the structure of a micro grid system based on small hydroelectric power generation according to an embodiment of the present invention.
3 is a conceptual diagram showing an example of the Phelton aberration in the small hydrostatic generator according to the embodiment of the present invention.
4 is a block diagram illustrating monitoring and control signals of an energy control unit in a micro grid system according to an embodiment of the present invention;
5 is a conceptual diagram illustrating a bypass flow path of a small hydro-electric power generator in a micro grid system according to an embodiment of the present invention.
6 is a flow chart illustrating a process of supplying small-hydroelectric power in a micro grid system according to an embodiment of the present invention;

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The present invention is a microgrid system for connecting a plurality of distributed power sources and controlling power supply therefrom, which is schematically shown in Fig. 1 and more detailed in Fig.

1 and 2, the micro grid system of the present invention includes a distributed power supply unit 100, an energy storage unit 200, a grid power supply unit 300, a user load unit 400, a DC grid unit 500, And an energy control unit 600.

First, the distributed power unit 100 generates power from a plurality of energy sources such as renewable energy. The distributed power unit 100 includes a small hydro-electric generator 110 that generates power using a small power.

The distributed power unit 100 may further include a solar generator 120 that generates power using solar light or a wind power generator 130 that generates power using wind power. Additional generators using renewable energy may be added.

In the embodiment of the present invention, the small hydrostatic generator 110 to which the pelton aberration is applied as shown in FIG. 3 is assumed, but the present invention is not limited thereto. The Phelton aberration system controls the flow rate of the water introduced into the hydraulic pipe and ejects the water through the nozzle at a high speed. The pellet aquarium system applies power to the bucket so as to generate power by rotating the wing car. Where appropriate.

Next, the energy storage unit 200 stores and manages electric power by charging / discharging the electric power generated in the distributed electric power source unit 100 to / from the battery. The energy storage unit 200 may be configured as a conventional ESS (Energy Storage System) including battery management and includes a function of monitoring the charge / discharge state, overcharge, power quality, temperature, and the like of the battery.

Next, the system power source unit 300 is a power source that is supplied with power by conventional thermal power generation. In this embodiment, a diesel generator 310 that uses a diesel engine is used. However, the present invention is not limited to this, and it is possible to connect the system power source such as KEPCO to supply system power.

The user load unit 400 may be a general household or a plant that consumes power. In particular, in the present invention, since the user load unit 400 is based on small hydrographic power, It can be a load.

Next, the DC grid unit 500 converts input voltages from the distributed power supply unit 100, the energy storage unit 200, and the grid power supply unit 300 into a common DC voltage, Converts the output voltage to the AC power supply 400, and distributes the power to each load.

Specifically, the DC grid unit 500 includes an AC-DC converter 510 for converting the AC voltage of the small hydro-electric generator 110 into a DC voltage, a DC-DC converter (stepping up the DC voltage of the solar generator 120) An AC-DC converter 530 for converting the AC voltage of the wind power generator 130 into a DC voltage, and a DC-DC converter 540 for boosting and reducing the DC voltage of the energy storage unit 200. The inverter / inverter circuit 520 converts the output voltage of the converters 510, 520, 530, and 540 to an AC voltage and supplies the AC voltage to the user load unit 400, and rectifies the AC voltage of the diesel generator 310 to a DC voltage. A rectifier 550 and a DC bus 560 connecting the outputs of the inverter / rectifier 550 with the converters 510, 520, 530 and 540 described above.

The energy control unit 600 integrally controls the distributed power unit 100, the energy storage unit 200, the grid power unit 300, the user load unit 400, and the DC grid unit 500, The use state and the output state of each component are monitored and the monitoring results are comprehensively analyzed to control the operation of each component and provide an optimal power distribution.

For example, the energy control unit 600 may be configured as a conventional EMS (Energy Management System), and may include a measurement function for measuring a voltage, a current, a temperature, and the like, and a function for displaying overcharge, overdischarge, overcurrent, And an alarm function for alarming, an analysis function for collecting and analyzing the measured data, and the like.

The main supervisory signals and control signals communicated between the energy control unit 600 and each constituent unit according to the embodiment of the present invention are schematically shown in FIG. In addition to those shown in FIG. 4, there may be various kinds of monitoring and control signals for maintenance and the like of the generator itself, but a description thereof will be omitted here.

4, the energy control unit 600 receives the flow state and output power state from the small hydro-power generator 110 and analyzes the flow state and the output power state to control the flow rate or flow rate of the flow path to control the output power of the small- do. The flow rate or flow rate of the flow path can be adjusted by adjusting the opening and closing degree of the water gate or the turbine of the small hydrostatic power generator 110.

Specifically, when the output power of the small hydro-electric power generator is excessively high, problems such as overvoltage and frequency rise may occur, and problems such as an increase in the number of revolutions of the turbine, a rise in temperature and a failure of the bearing may occur. In addition, if the turbine is not used due to failure or repair, the turbine may be subjected to over-rotation or over-voltage. Therefore, it is necessary to control the flow rate or the flow rate by adjusting the opening / closing degree of the water gate depending on the output state of the generator.

To this end, the small hydrostatic power generator 110 of the present invention further includes a bypass flow path for bypassing the flowing flow amount, and a sensor (not shown) installed at a plurality of points of the flow path to measure flow rate or flow rate.

As shown in FIG. 5, the bypass flow path 112 is installed in parallel with the flow path 111 in which the generator is installed, and is provided with the water gates 113 and 114 for controlling the flow path.

The energy control unit 600 controls the degree of opening and closing of the water gates 113 and 114 according to the flow rate or flow rate measurement value obtained from the flow rate or flow rate sensor and the output state of the small hydropower generator 110, Can be protected. At this time, the measured value of the flow rate or flow rate sensor may cause a delay or an error depending on the measurement position. Accordingly, in the present invention, the flow rate or the flow rate is measured by a plurality of flow rate or flow rate sensors, and the flow rate or flow rate value is determined by combining them.

,

,

F: Determined value of flow rate or flow rate

F _n : measured value of nth sensor

N; Number of installed sensors

k _n : Weight according to the distance of the nth sensor

Here, the weight k _n is a weight value according to the distance between the position _where the sensor is installed and the gates 113 and 114. The shorter the distance, the higher the weight.

As described above, by accurately determining the flow rate or the flow rate value based on the measured values of a plurality of flow rate or flow rate sensors, the degree of the separation of the watersheds 113 and 114 can be precisely controlled. In addition, even if some sensors fail, it is possible to lower the error rate of the flow rate or flow rate, so that the turbine can be safely protected from over-rotation or over-voltage.

Meanwhile, the energy control unit 600 receives the notification of the level of charge / discharge power from the energy storage unit 200, and controls charging / discharging operations and power supply. The diesel generator 310 receives the power supply status, Control whether or not to supply. In addition, the user load unit 400 is informed of the usage amount of each load, and power is selectively supplied to each load. The DC grid unit 500 is informed of various converters and voltage currents of the inverters, Thereby controlling the voltage conversion operation.

In the present invention, since the small-scale hydroelectric power generation is used as the main distributed power source, it is necessary to control the power supply of the small hydro-power generation as shown in Fig.

First, the energy controller 600 compares the amount of small hydraulic power generated by the small hydropower generator 110 with the load usage of the user load unit 400, and then confirms the state of charge of the energy storage unit 200.

Next, the energy control unit 600 controls power supply based on the above-described small-hydro-power amount, load usage amount, and charging state as follows.

Step a : If the small hydraulic power is equal to the load usage (Phydro => Pload), the small power is supplied to the user load unit 400 (Phydro -> LOAD). Where "Phydro" is the small hydro power and "Pload" is the load usage. In addition, the expression " the same " does not mean a perfect match but includes a certain degree of error range.

Step b : When the small-hydroelectric power amount is smaller than the load usage amount and the charging state of the energy storage unit 200 is higher than a predetermined level (Phydro <Pload, Pess> Pref), the charging power of the energy storage unit 200 To the user load unit 400 (Pess - > LOAD). Here, " Pess " is the discharge power amount of the energy storage portion, and " Pref " is the minimum stored power amount capable of discharging operation of the battery.

Step c : The system power of the grid power supply unit 300 is supplied to the user (not shown) in addition to the small power power, when the small power capacity is smaller than the load usage and the charge state of the energy storage unit 200 is less than a predetermined level (Phydro < To the load unit 400 (Pgrid -> LOAD).

Step d : In the case where the small hydroelectric power is larger than the load usage and the charging state of the energy storage unit 200 is not full (Phydro> Pload, Pess <Pful), the small power power is supplied to the user load unit 400, And charges the storage unit 200 (Phydro - > ESS). This is the case where the battery of the energy storage unit 200 is charged by the small-hydropower power, where " Pfull " is the amount of power in a state where the battery is fully charged.

Step e : If the small hydroelectric power generation amount is larger than the load usage amount, and the energy storage unit 200 is in a fully charged state (Phydro> Pload, Pess≥Pfull) Control power generation (Phydro-Pload -> 0).

As described above, by controlling the supply of the small hydropower generation power, it is possible to efficiently use the generated power of the small hydropower generator, appropriately protect the small hydropower generator, and supply environmentally-friendly generated electricity stably to a large number of users.

While the present invention has been described with reference to the preferred embodiments described above and the accompanying drawings, it is to be understood that the invention may be embodied in different forms without departing from the spirit or scope of the invention. Accordingly, the scope of the present invention is defined by the appended claims, and is not to be construed as limited to the specific embodiments described herein.

100 Distributed power unit 110 Small power generator
120 Solar power generator 130 Wind power generator
200 Energy storage unit 300 system power supply unit
310 diesel generator 400, 410, 420, 430 user load part
500 DC grid unit 510, 530 AC-DC converter
520, 540 DC-DC Converter 550 Inverter / Rectifier
560 DC bus 600 Energy controller

Claims (9)

As a micro grid system based on small hydropower generation,
A distributed power source section for generating electric power from a plurality of energy sources;
An energy storage unit for storing and managing electric power by charging / discharging electric power generated in the distributed power unit to / from a battery;
A system power supply for generating system power;
A user load unit that consumes power generated by the distributed power unit and the grid power unit;
A DC grid unit for converting an input voltage from the distributed power source unit, an energy storage unit, and a grid power source unit to a common DC voltage, converting an output voltage to the user load unit to an AC voltage, and distributing power;
And an energy control unit for monitoring the states of the distributed power unit, the energy storage unit, the grid power unit, the user load unit, and the DC grid unit, and controlling each operation according to the monitoring result,
The distributed power unit includes:
A small-scale hydroelectric generator for generating electric power using small hydroelectric power, a solar generator for generating electric power using solar light, and a wind turbine generator for generating electric power using wind power,
Wherein the energy control unit comprises:
Monitoring the flow state and output power state of the small hydropower generator and controlling the output power of the small hydropower generator by controlling the flow rate or the flow rate of the flow path according to a monitoring result,
Wherein the control unit compares the small hydraulic power amount generated by the small hydro-electric power generator with the load usage amount of the user load unit and monitors the charging state of the energy storage unit,
a) supplying the small-capacity power to the user load section when the small-hydro-power amount is equal to the load usage amount,
b) if the small hydraulic power amount is smaller than the load usage amount and the charging state of the energy storage unit is equal to or higher than a predetermined level, charging the user load unit with the charging power of the energy storage unit together with the small-
c) supplying the grid power of the grid power unit to the user load unit together with the small-hydro power when the small-hydropower power amount is smaller than the load usage amount and the charging state of the energy storage unit is less than a predetermined level,
d) supplying the small-capacity power to the user load unit and charging the energy storage unit when the small-hydroelectric power amount is larger than the load usage amount and the charging state of the energy storage unit is not full,
e) controlling the power generation amount of the small hydropower generator such that the small hydraulic power amount is equal to the load usage amount when the small hydraulic power amount is larger than the load usage amount and the charging state of the energy storage part is full,
The system power supply unit includes:
A diesel generator for generating electricity using a diesel engine,
The small-
And a flow rate or flow rate sensor installed at a plurality of points of the flow path to control an inflow flow rate and a flow rate of the inflow,
The DC grid unit includes:
An AC-DC converter for converting an AC voltage of the small hydro-electric generator into a DC voltage;
A DC-DC converter for boosting a DC voltage of the solar generator;
An AC-DC converter for converting an AC voltage of the wind power generator into a DC voltage;
A DC-DC converter for boosting and reducing the DC voltage of the energy storage unit;
An inverter / rectifier for converting an output voltage of the AC-DC converter and the DC-DC converter to an AC voltage and supplying the AC voltage to the user load unit, and rectifying the AC voltage of the grid power unit to a DC voltage; And
A DC bus connecting the output of the AC-DC converter, the DC-DC converter, and the inverter / rectifier,
Wherein the flow rate or flow rate value of the flow path is determined based on the measured value from the flow rate or flow rate sensor as follows:

,

F: Determined value of flow rate or flow rate
Fn: measured value of nth sensor
N; Number of installed sensors
kn: Weight according to the distance of the nth sensor

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