Charting the rise of the smart grid and what it means for energy users
As the world reflects on its energy use amid the Covid-19 pandemic, the use of renewable energy is coming to the fore. Managing energy demands via the smart grid is the next step to a sustainable energy supply. Relec Electronics’ Mornsun portfolio supports the current demand for smart grid implementations to provide a cleaner, more sustainable energy supply.
Smart grids are a necessity in the modern world with their ability to react to changes in both supply and demand of electrical power. Coupled with the evolution of smart grids, there is a high demand for power electronic solutions that are efficient, effective, and reliable.
Figure 1: The smart grid uses data to control and communicate power needs.
What is a smart grid?
A smart grid uses information technology, automatic control and communications to generate, transmit and distribute power. Using data and analytics, as well as devices such as smart meters, it allows energy to be generated, distributed and consumed efficiently.
Smart grids use a mix of energy sources (many of which are renewable) to provide an environmentally responsible, reliable solution to electrical power needs. Smart grids are efficient, compatible with smart devices and smart homes, and support the growing use of electric and hybrid vehicles. They also lead to economic savings and better management of energy consumption.
The smart grid is increasingly in popularity as a means to connect various distributed energy resource assets to the power grid, to manage and distribute energy. Data collection means that a smart grid can be self-healing when it detects service issues, instead of having to wait for a customer to report outages. For renewable energy, a smart grid can transmit information to energy generators and use data from their sensors to determine climate and environmental conditions to adjust energy demands according to needs.
Research from Markets+Markets, predicts that the smart grid market will benefit from an international drive to use renewable energy sources in place of fossil fuels to protect the environment. Driven by a need to modernise the grid infrastructure and increased awareness about the management of our carbon footprint, it predicts that the smart grid market will be worth $61.3 billion by 2023, a compound annual growth rate of 20.9% between 2018 and 2023.
Renewable energy sources
Within a smart grid, the major actions that take place are power generation, transmission, transformation, distribution and consumption. Figure 2 shows a typical block diagram for a smart grid. Power is routinely generated by multiple sources, for example, wind turbines that include a wind-solar complementary controller, or a nuclear power plant with oxygen quantity analyzers, or solar (Photovoltaic or PV) panels with a heliostat solar tracking systems.
Figure 2: Elements in a typical solar (PV) smart grid system
Once the power has been generated within PV systems, there is often a need to convert or invert the electricity to its correct form, and at the right voltage, for transmission. This may include distributed inverters, DC-AC converters, and DC-DC converters. Energy routers ensure the electricity goes to the right place within a power generation system. Another key aspect within a smart grid system is a DC distribution cabinet, which includes a combiner box (linking multiple solar arrays together) and centralized inverters. From there, the power heads to the power lines for transmission to consumers or end users.
Mornsun offers the latest, advanced effective power electronics for smart grids, ranging from power generation to distribution and use within homes and businesses. These solutions address key issues in power generation, such as efficiency and safety. They also address electrical challenges such as wide input voltage ranges, high input voltages, small footprints, adequate isolation, and high efficiency at both full load and under low load conditions.
Building solar networks
Large scale photovoltaic systems are made up of multiple solar arrays, and the combination of these arrays (or strings) is largely determined by the inverters used. Combiner boxes provide surge protection, fuse and switch disconnects, as well as system monitoring. Mornsun’s PV series DC- DC converters have input ranges from 100V to 1500Vdc allowing the all of the control elements withing combiner boxes to run directly from the solar array itself, increasing efficiency and reducing complexity.
Another critical element in smart grids is power transmission. Technology has been steadily evolving, beginning with distribution voltage and rising to high and ultra-high voltage. Transmission has also changed, beginning with high power, medium distance transmission, shifting to long distance transmission and finally to long distance power system interconnection. For power transmission, Mornsun offers a variety of power efficient solutions compatible with today’s ultra-high voltage, long-distance power systems such as the PV75D-36D DC-DC converter series. This modules have an input range of 250 to 3300Vdc and isolation levels up to 6000Vac making them suitable for use as components for monitoring traditional power grids. They are typically used in renewable energy industries (PV, power generation, energy storage, inverters and high-voltage DC conversion. They guarantee stable and safe operating environments, even under abnormal working conditions. Power transformation is also critical to modern smart grids, providing key functions such as monitoring and control of the current and voltage and other parameters, with the goal of ensuring equipment safety and power quality.
A robot for overhead power line inspection is an interesting example of such an application. In the UK, network operator, Scottish and Southern Electricity Networks (SSEN) partnered with Williams Advanced Engineering to design an autonomous, overhead line inspection robot for its high voltage electricity networks.
The Line Inspection by Semi-Autonomous Systems (LISAS) project, funded by Ofgem’s Network Innovation Allowance, was to create a robot system that can navigate across steel towers, capturing critical asset data in maintenance inspections on the live overhead lines. Maintenance teams can carry out essential work on the infrastructure to inspect and maintain networks while they remain live to minimise disruption to customers in the north of Scotland and central southern England. Robots can supply up-to-date asset and safety data, photographs and video to help the supplier to formulate a maintenance and replacement programme to meet increased demand for electricity.
Power distribution is another key aspect in a smart grid, including the power supply unit of the Data Transfer Unit/Feeder Terminal Unit (DTU/FTU). (The DTU and FTU are switch monitoring devices installed in the sub-station to monitor and communicate the distribution network.)
Power distribution focuses on system continuity power supply requirements, EMC protection, and the high isolation power supply of the telemetry system. Mornsun offers a range of products for such applications including high isolation DC-DC converters, and isolated bus transceiver modules for CAN/RS485 and RS232 communication.
The transceiver modules integrate a transceiver, isolation chip and high efficiency isolated dc-dc converter. They are compact, high reliability, low power consumption modules in one single module. They are designed for use in harsh environments and can be supplied in CAN bus, RS232 or RS485 formats, according to individual requirements.
Industrial and commercial power consumption
The final destination on the path of power through a smart grid is end-user consumption. One of the latest developments in this area is smart meter technology. Smart meters allow two-way, real-time communications between energy distribution companies and consumers, using GPRS.
Many countries around the world have introduced government-funded, large-scale smart meter rollouts. Smart electricity meters are welcomed because they can help track energy usage and reduce the reliance on fossil fuels. As a result, the global smart meter market is expected to be worth nearly £22,000 million by the end of 2025, according to Valuate Reports (https://reports.valuates.com/market-reports/360I-Auto-1L64/smart-meter-market).
Smart meters can provide efficient management of utilities (gas, water and electricity). They are also instrumental in smart homes where they can be used for automated monitoring of energy for appliances as well as power, light and energy.
This level of automation requires higher levels of communication interfaces, large-capacity memory and microprocessors, wide voltage input, low power consumption, small form factor and high-level EMC protection for the power supply. Mornsun has the power electronics that meet the specifications for these kinds of applications including products such as the LS series 1 – 15W, high density, low cost Ac-DC converters and high efficiency, low power, DC-DC converters
The LS series converters are designed for where space is limited. They are supplied in high-density, vertical single-in-line package (SIP) devices range from 1W to 15W in compact form factors from 35 x 18 x 11mm to 44.5 x 24 x 15mm.
Energy storage inverters
The majority of the energy generated with PV is systems goes straight to the supply grid, but there is increasing need to store excess energy in batteries. Figure 3 is a detailed block diagram of a typical energy storage inverter, used in a real-world smart grid. This inverter design includes many components from Mornsun’s portfolio.
Figure 3. An energy storage inverter, typically used in a smart grid
The Mornsun QP12W08S-37 is particularly well-suited to use in smart grid inverters. It is a fully integrated IGBT driver with built-in isolated DC-DC power supply, with a high isolation voltage of 3750Vac. The QP12W08S-37 can accommodate input signals at frequencies up to 20 kHz and has built-in fault protection together with a pin for fault feedback to ensure reliable operation.
Mornsun’s TDx01D485H Series of isolated bus transceiver modules, allows external systems to communicate with the monitoring system via an RS 485 network. The modules uses integrated IC technology to create isolation between the power supply and the signal line, as well as transmitting data and protecting the communication bus, in a single module. This series of products can be easily embedded in end-user equipment to achieve a fully functional RS485 network connection.
The MCU used in this design is powered by the Mornsun series of DC-DC converters, specifically the Mornsun B0503XT-2WR2. This converter has efficiency up to 84%, high power density, and a wide operating ambient temperature range, making it particularly suitable for use in a photovoltaic (PV) invertera, as well as a host of other applications. Figure 3 also shows the use of two switching regulators for generating 5V rails from a 24V input supply. These include the K7805-500R3 model, which offers efficiency of up to 95%, a no-load input current as low as 0.2 mA, and output short-circuit protection as standard.
The design requires a 200 to 1500Vdc input voltage isolation converter and Mornsun’s PVxx-29B24 series is the ideal choice for this application. This line of single output isolation converters has been designed primarily for use in the PV industry. Converters feature high efficiency and high reliability, as well as a high level of safety. They have efficiency up to 80%, 4000Vac isolation, a wide operating temperature (-40°C to +70°C) and have reverse polarity input, output over-voltage, over-current and short circuit protection as standard.
DIN Rail mount versions A8 (integrated EMC Filter) and A10 options are also available with screw terminals and CE approvals.
Smart grids are increasingly common and Mornsun is a single source supplier for power electronics for this burgeoning market. Its portfolio includes components for smart grids, battery management systems, combiner boxes, inverters, and grid monitoring units, as well as end-user applications such as electric vehicle / hybrid electric vehicle (EV/HEV) charging stations. The range of power electronic products provide efficient, reliable, high power-density products for smart grid projects.
A keen interest in renewable energy sources has been strengthened by the recent global, Covid-19 pandemic which saw many traditional industries shut down or reduce operating hours. Use of renewable energy increased by 10% in the UK, compared with 2019’s usage. In Germany it increased by 12% compared with 2019 to account for 60% of the country’s energy source, reports Wärtsilä Energy.
Relec Electronics is a specialist in power conversion and display products, representing leading brand names including Mornsun in power conversion alongside Bel Power, Chinfa, Cotek and Premium with key display partners, Digiwise and RockTouch.
Relec’s team of specialist advisers can refine an initial specification for a given application to include bespoke features to meet the needs of a particular design or project.
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