The schematic diagram of the grid-tied solar power system

What is grid-tied solar power?

Grid-Tied PV System, also known as “On-Grid” solar power system, is a solar power generation system that is directly connected and connected to the grid. at the connection point, the generated electric energy is mixed into the public power system and jointly supplied to the loads for use, when the electrical energy generated from the system is less than the demand of the load, a part of the energy is offset from the public grid and vice versa when the demand for electricity is less than the amount of electricity generated, the excess energy of the system will be “flowed” into the grid. In this solution, the public grid system plays the role of both providing energy, storing and regulating energy, so that the solar power system is always controlled for maximum power generation without the need for electricity. must self-regulate according to the load demand to make full use of this clean energy source, besides, there is no need to calculate and balance the power consumption of the load when designing and installing the solar power system as well. as there is no need to invest in a battery / storage battery system to “back-up” and regulate energy.

System Operation:

Solar panels are connected to each other in arrays and installed to best capture energy from the Sun’s radiation and convert it into electricity in the form of direct current, this current will be Inverter (Inverter) modulates into alternating current and automatically adjusts electrical parameters such as voltage, frequency, phase angle to satisfy the conditions of harmonization and connection to the grid at the connection point, this inverter is called Grid-tied solar inverter.

Benefits of the solution:

The grid-tied solar power solution solves many disadvantages for solar energy, which is an intermittent energy source and cannot control the source but only the receiving system. Utilizing the electrical system as a storage, conditioning and co-supply system for the load will allow maximum solar energy collection and bring many benefits.

• Unlimited load, make the most of:

  The system allows maximum solar energy collection and does not need to calculate the load balance when investing in the system and is not required to limit the consumption capacity of the load.

• Flexible investment:

  The capacity can be invested in accordance with the conditions of the installation area and can be divided into many investment stages in accordance with the investment ability.

• System with high stability, long service life:

  The main equipment in the system such as panels, inverters are manufactured with durability and design life of over 20 years and do not use battery/storage batteries which are low-durability devices.

• Low investment cost:

  Because there is no need to invest in a battery/battery system, this solution significantly reduces investment costs compared to a standalone system (Off-Grid).

• Low operating and maintenance costs:

  The main units are designed to be maintenance-free or low-maintenance and operate fully automatically without the need for operator along with allowing remote monitoring via PC and mobile devices, so the system has almost no operating costs.

Cons of the solution:

The grid-tied solar power solution brings many benefits, but there are also disadvantages that investors need to consider when deciding to invest.

• Không vận hành được khi mất điện:

  Because the system is connected to the public grid, when the power grid loses power, the system will automatically separate from the power system, which means that if there is a power outage to the public grid, the load will also lose power according to the surface. This is during sunny times and of course not in areas without electricity.

• Must be licensed:

  The public power system is like a “buffer” so the connection to the grid must be approved by the Electricity and the State management agency and the system must meet the standards as well as the power quality according to the regulations. determined. In Vietnam, the connection of the power system to the grid has been allowed under the Prime Minister’s Decision No. 11/2017/QD-TTg and specified in the Circular No. 16/2017/TT-BCT of the Ministry of Industry and Trade. with the active support of EVN.

• System Limits:

  The use of the public electricity system as a “buffer” system (storage and conditioning), so the total capacity of solar energy in a country or region depends on the “conditioning” capacity of the system. in that country or region. In Vietnam, according to the power plan VII, the total capacity for renewable electricity including Wind power, Solar power and Biomass power is 850MW by 2020 and expanded by 4,000MW by 2030. However, this should be done. interested in solar power generation plants with large capacity up to tens of MW.

The main devices in the system:

• Solar panels:

Solar panels are installed to maximize energy from solar radiation

• Solar panels are linked into arrays, installed to absorb maximum energy from solar radiation and convert it into electricity. Solar panels account for most of the investment costs and are decisive in terms of energy conversion efficiency.

• Solar inverter:

The solar inverter is the heart of the system.

• Solar inverter is likened to the heart of the system, determines the stable operation of the system and determines the quality of power produced, so this is the most important device of the system.

• Intermediate and protection systems:

Electrical cabinet with DC connection to link solar panels and protect the system

• This system consists of conductors and equipment for connection, switching, measurement and protection installed inside the electrical cabinet.

• Two-way galvanometer:

Nhân viên Điện Lực lắp đặt điện kế hai chiều tại 1 dự án

Two-way galvanometer (Net-metering) is often supplied and installed by Electricity agencies to measure power in two directions, in the direction of electricity consumption and in the opposite direction, to generate electricity to the grid. The measurement of these two power flows serves as the basis for calculating electricity bills according to the “offsetting” mechanism.

Power monitoring system solutions

Energy monitoring system (Power monitoring) is a system consisting of multi-functional measuring devices with high sampling rate, multi-parameter analysis, allowing connection to the system and communication connection with the system. computer to store data. Specialized software will analyze data for the display and measurement of energy consumption, monitor the operation of the power system in real time, control the power system remotely by computer, store and analyze Analyze usage data and generate power system energy consumption reports.

The main functions of the system.

• Draw a schematic diagram of the electrical system.
• Displays electricity and energy parameters in real time.
• Storing electrical data for energy statistics and analysis.
• Plot the load graph in real time.
• Analysis of load power usage.
• Power quality analysis.
• Early warning of faults in the power system.
• Remotely control the closing and cutting of electrical equipment.
• Monitor the operation status of power consuming equipment.
• Generate energy reports.

Components of the system:

Structure diagram of power monitoring system (power monitoring)

• Measuring/actuating system:

Multi-function measuring device

The meter is installed in the electrical cabinets responsible for measuring electrical parameters at the branches according to the design, storing the parameters locally and transmitting digital information to the central computer system by the Modbus RTU, ICP transmission line. /IP, Ethernet. The meter has 3P-4W-380V voltage inputs, 3P-4W-5A line inputs to provide measurement current and voltage, RS 485/ RS 232 and Ethernet communication ports to help establish solutions Communication, Binary inputs, Binary outputs for system control and device status monitoring, USB port for connection to a computer when programming, Memory card slot for local data storage and upload onto the system.

• Communication network system:

The communication network system is established to connect devices together and transmit information about the host system.

• Host system.

The server system is used to store data and install energy monitoring software to analyze, display online the status and power network system.

• Energy monitoring software:

WinPQ software has the function of storing and analyzing power data, displaying online the status and power network system, remotely controlling switchgear, which is a tool to help customers easily manage and monitor, operate the power system remotely through a computer, store data and make reports on electricity to help monitor the energy system.

Solar pump system was installed by Tran Le in Gia Lai

What is solar water pump?

Solar pump is a solution to harness solar energy to provide a water pumping system that works without electricity. The system consists of solar panels that are combined and installed to receive solar radiation energy and convert it into DC electricity, which will be used by a dedicated inverter for pumping. Solar pump inverter (solar pump inverter) converts into alternating current to power the pump. The inverter will automatically adjust the frequency to adjust the pump’s power consumption to match the power received from the sun at different times, this operating mechanism helps the water pump operate smoothly without any problems. need to supply power or set up a storage system.

Solution benefits.

• No fuel or electricity costs:

  100% of pump power is harnessed from the sun without electricity or diesel fuel to run the generator.

• No need to invest in power lines or generators:

  The system can operate independently without power, so there is no need to invest in power lines or generators, especially for some farms located far from the center, this reduces a lot of investment costs. private.

• Automatic operation without operating costs:

  The system operates completely automatically without human control so there is almost no need for operating costs.

• Durable operation, long service life:

  The main equipments are designed and manufactured with durability and service life of over 20 years, so the system can operate very stably for a long time.

• Help the water pump work durable:

  The water pump motor is controlled by inverter technology with a full range of protection functions to help the water pump operate stably, durable, and less damaged.

• Flexible Operation:

  The system still has an AC power input that allows power to the grid or from a backup generator to use the pump when it is less sunny or at night, giving users flexibility in use.

The main device of the system.

The main equipment of the system including the water pump is a 3-phase electric pump  normally connected to the battery and control system consisting of solar panels and a solar pump inverter.

• Solar panels:

  This is the main device to help convert radiant energy into electrical energy, the panels are combined and installed to receive the best energy from solar radiation.

• Solar pump inverter:

  The inverter helps to convert the DC power from the panels into 3-phase AC with the appropriate frequency to control the water pump according to the energy obtained at different times, in addition, the inverter also integrates the following functions. Protection for water pump such as overload, short circuit, phase unbalance..etc.

• Water pump assembly:

  The water pump is a 3-phase electric pump that can be a submersible rocket pump for wells or a conventional centrifugal pump.

• Other auxiliary devices:

  Including conductors, switchgear, protection, relays, control sensors to link the system depending on the needs of use.