Abstract
The demands on distribution grids are increasing worldwide due to the growing use of photovoltaics, heat pumps and electromobility. These developments are leading to voltage problems in the grid, particularly in Europe, where expensive grid expansion is already taking place. In South Africa, on the other hand, the focus has so far been on the availability of electricity. However, with the strong growth of the solar market, grid stability is becoming increasingly relevant here too.
One example of a modern solution is the introduction of the A. Eberle »LVRSys®«- Low Voltage Regulation System at the Siemens data centre in Midrand, South Africa. The project shows how »LVRSys®« contributes to voltage stabilisation in critical infrastructure – especially in regions undergoing a transition to renewable energies. In addition to South Africa, the technology is also an economical alternative to traditional grid expansion in Europe and worldwide, as it can be used flexibly, cost-effectively and independently of location.
LVRSys®
The »LVRSys® – Low-Voltage Regulation System« was developed to solve voltage stability problems due to the integration of electromobility, photovoltaics and heat pumps in the low-voltage grid. It represents an economical and flexible alternative to costly and time-consuming line extensions.
Energy Supply in Europe and South Africa Today: The Need for Innovative
and Sustainable Solutions
The demands on distribution networks are increasing rapidly worldwide. Voltage fluctuations are becoming more frequent as photovoltaic systems raise voltage levels in low-voltage grids, while the growing use of heat pumps and electric mobility leads to voltage drops. While photovoltaic systems dominate voltage levels during the day, heat pumps and electric vehicles primarily cause voltage reductions in the evening and at night. Additionally, the single-phase charging of electric vehicles exacerbates phase voltage asymmetries
In Germany and Europe, these effects have led to rapid and costly grid expansion. At the same time, there is an increasing demand for intelligent solutions that enable quick and cost-effective grid stabilization.
In South Africa, the focus so far has been more on the availability of electricity rather than grid stability. However, this trend is expected to intensify in the coming years with the rapid expansion of renewable energies. The South African solar market is estimated to reach 6.68 gigawatts by 2024 and is projected to grow to 11 gigawatts by 2029, reflecting an annual growth rate of nearly 11 percent. According to the International Renewable Energy Agency (IRENA), wind and solar energy capacity is expected to reach 20 gigawatts by 2030.
In the long term, market growth will be driven by the increasing demand for clean energy sources and efforts to reduce reliance on coal-fired power plants. At the same time, the necessary expansion of the high-voltage grid by Eskom remains a critical challenge in integrating renewable energy into the existing power infrastructure. Therefore, the increasing share of renewable energy requires innovative and sustainable solutions to ensure grid stability while advancing the decarbonization of the energy sector.
he main challenge in South Africa remains the secure and stable supply of electricity and the achievement of climate targets in accordance with the Paris Agreement. South Africa is currently one of the 20 largest CO2
emitters in the world, as electricity production is heavily dependent on coal and liquid fuels. In addition, inadequate maintenance and power plant expansions that cannot really be planned lead to large voltage fluctuations time and again. These impair the function of operating
equipment, which can lead to production disruptions in industry and even the destruction of devices. Standards such as EN
50160, IEC 61000-2-12 or the South African NRS 048 define voltage band limits (±10%). Machines, drives and lighting work most efficiently at nominal voltage. Outside this range, efficiency and service life decrease, especially with LEDs. A pilot project between Siemens Proprietary Limited in Midrand South Africa and A. Eberle Africa (Pty) Ltd. in Durban South Africa demonstrates how a »LVRSys®« Low Voltage Regulation System ensures the voltage stability of a data centre. It reacts to fluctuations in the grid voltage within 30 ms and thus ensures that this critical infrastructure is fully operational 24/7. An »LVRSys®« with a nominal output of 250 kVA (+10%) with eight control steps is used in the pilot project.
»LVRSys®« – Low Voltage Regulation – Principle of Operation
Figure 7 (left): »LVRSys®« control stage area
Implementation of Efficient Voltage Stabilization with »LVRSys®«
The Siemens data centre in Midrand, South Africa, was previously using older system technology that no longer fully met current requirements and was based on servo motor control with mechanical stage adjustment. This technology had a long response time of several minutes, low efficiency and qualitative limitations, which led to increased maintenance costs and extended downtimes.
In view of these challenges, the decision to replace the existing system with the innovative »LVRSys®« – Low Voltage Regulation System was an easy one. This reliable and robust technology enables high-precision voltage regulation with a response time of less than 30 milliseconds, which efficiently compensates for voltage fluctuations. This ensures the continuous and uninterrupted operation of the data centre, which is essential for Siemens.
The dismantling and environmentally friendly disposal of the old system was carried out by a local partner company in collaboration with A. Eberle Africa: INSTELEC SERVICES CC, contact: info@instelec.co.za
The pilot plant was dimensioned according to the latest standards and included the following technical features:
A key feature of the »LVRSys®« is its exceptionally high efficiency, which is between 99.4 % and 99.8 % in all available power classes. This makes the system a particularly energy-efficient and environmentally friendly solution. The system also impresses with its outstanding performance values compared to other technologies available on the market:
- Throughput power: 22 kVA to 2500 kVA
- Control ranges: ± 6 % to ± 16 %
- Number of stages: 9
- Efficiency: 99.4 % – 99.8 %
- Control: phase-independent
- Mains feedback-free
- Increase in single-pole short-circuit power through pre-stage up to 44 kVA
In addition, the »LVRSys®« is deliberately designed to be user-friendly and low-maintenance. The recommended function check only requires a manual change between bypass and normal operation every five years. A. Eberle Africa also provides a local after-sales service. The system is supplied with a five-year warranty and has an expected service life of 40 years.
Power Quality Monitoring Parallel to »LVRSys®« Voltage Regulation
Another outstanding feature of the built-in low-voltage control system is the integration of two optional »PQI-DA smart«, power quality devices, high-precision Class A measuring devices in accordance with IEC 61000-4-30, Ed. 4. These continuously record and document both input-side voltage changes and the regulated output voltage. This means that the functioning of the system is continuously monitored and can be traced at any time. An integrated 1GB memory enables long-term voltage monitoring. In addition, the built-in power quality devices communicate via a TCP/IP interface with the database-orientated system software »WebPQ«, which ensures comprehensive data evaluation and analysis.
Successful Commissioning of »LVRSys®«
The »LVRSys®« was successfully commissioned by A. Eberle Africa in July 2024. The system has been working reliably and without any problems ever since. The user-friendly design also means that commissioning can be carried out independently by the end customer if required. In this case, training on operation and maintenance was offered in parallel to ensure optimum utilisation and long-term operational reliability
»LVRSys®« – Data Center Use Case
Customer: Siemens Proprietary Limited South Africa
Our focus is on the further development of innovative technologies, the design of decarbonisation pathways and the establishment of circular renewable systems for a sustainable transformation. The foundations for a successful energy transition by 2040 must be laid now. We have the opportunity to realise this – now is the right time to act, and Siemens Africa is leading by example.
Installation »LVRSys®«
Siemens Proprietary Limited South Africa
300 Janadel Avenue
1685 Midrand, South Africa
07/2024
Pilotprojekt in Südafrika im Rahmen des RES-Programms
Application: Voltage Stabilization of Critical Infrastructure – Data Center
The EN 50160 and NRS048 standards define, among other things, the permissible voltage ranges within which the mains voltage must remain. The permissible tolerance is ±10 % in relation to the nominal voltage UN_U_NUN (400 V phase-to-phase conductor), which means a permissible voltage fluctuation of 80 V around the nominal value. Machines, drives and lighting systems work most efficiently when the voltage applied corresponds to the optimum operating point – usually the nominal voltage of the mains supply. If the voltage deviates from this, both the efficiency and the service life of electrical drives are reduced. Lighting systems in particular, such as LEDs, are sensitive to voltage deviations, which significantly reduces their service life. In industrial applications, voltage stabilisers with response times of less than 30 milliseconds can be configured to solve these problems. Industrial systems and machines are typically operated with a three-phase power supply. Three-phase industrial systems operate most efficiently at the nominal voltage UN_U_NUN (e.g., 230 V line-to-neutral), leading to potential energy savings. Voltage control corrects asymmetries between L1/L2/L3, resulting in improved efficiency and extended component lifespan (e.g., lower alternating cycles for motor
brushes).
Technical Solution A. Eberle »LVRSys®«
250 kVA ±10 % (180.1000.4019 355 A ±10 %)
»LVRSys®« – Application Scenarios for Utilities (EVU)
Expertise in Low-Voltage Regulation
Germany and Europe, but also increasingly other countries that are systematically driving forward the energy transition, are faced with the challenge of ensuring a stable grid voltage at the low-voltage level. Intelligent voltage regulation solutions are essential in order to delay cost-intensive grid expansion or – depending on future local grid planning – even avoid it completely.
Low-voltage grid development over several years – growth in renewable energy, heat pumps and e-mobility – and classic but cost-intensive grid expansion.
Low-voltage grid – flexible, intelligent solution with a »LVRSys®« low-voltage control system.
The »LVRSys®« low-voltage control system offers an efficient alternative to conventional line extensions by postponing or even completely avoiding them. Its economical use makes sense in almost all low-voltage grids. While investments in new lines tie up capital for decades, »LVRSys®« requires comparatively low investments, which can also be used flexibly and regardless of location. Should the grid structure change fundamentally, the system can easily be relocated to another site and continue to be used.
Authors
Till Sybel: Managing Director A. Eberle Africa (Pty) Ltd.
Nhlanhla Mbuli, PrEng, FSAIEE, SMIEEE: University of South Africa, Department of Electrical and Smart System Engineering
Marco Rahner: Siemens Proprietary Limited South Africa Smart Infrastructure Sales RC-ZA SI S
Brian Howarth: Managing Director A. Eberle Africa (Pty) Ltd.
This project is being funded as part of the Renewable Energy Solutions programme of the Federal Ministry for Economic Affairs and Climate Protection’s Energy Export Initiative.
