The hydrogen industry is young, and the technology is still developing. One growing area is the efficient and safe operation of electrolysers and fuel cells. Due to the explosive character of hydrogen, this is a very important task. In addition to measuring the gas concentration and the flow of fluids, the monitoring of the electrical characteristics of an electrolyser, rectifier or fuel cell has become common. This is easier and safer than measuring gas and fluids only.
A major player in this area is the German manufacturer, Muetec Instruments. This is the only company offering SIL2-certified transmitters for electrical monitoring up to 1500 V, allowing safety loops for electrolysers and fuel cells to be built that are redundant and failure proof. These transmitters protect operators from electrocution, and safeguard the equipment from damage by voltage peaks. To achieve this, Muetec’s SIL2 transmitters generate safe alarms and shutoffs based on the measured voltage or current. They are easy to program, and only need to be checked and recalibrated after ten years.
Monitoring of earth faults
A common application when monitoring electrolysers is the detection of earth faults. Nearly all electrolysers, and many fuel cells, are insulated from ground. With fluids running through the system, there is always the risk that an electrical potential builds up on a stack. Touching the device can be dangerous, and operators need to be alerted before they are at risk. If a stack gets electrically out of balance, this is also an indication that there is a leakage of fluid in the system.
To realise a safe earth, fault monitoring of one high voltage transmitter (HVT) is done per stack by measuring the outside electrodes against earth in the middle of the stack.
Single cell voltage monitoring
The most complete system to monitor an electrolyser is the single-cell voltage monitor. This is also the most expensive, and some manufacturers, especially of PEM electrolysers, use it during the prototype phase only. Each cell is individually connected with the central measurement device, and the voltage values of all cells are recorded in real time. For a large electrolyser this means that thousands of measurement values are stored per second to analyse and detect inefficiencies, possible defects and cell deterioration. By comparing the voltage measurement of each cell and analysing how it develops over time, it is possible to detect membrane pinholes and other defects, and plan preventive maintenance.
Critical success factors for this form of measurement are the speed of data processing based on the use of fast glass fibre connections, high processing power, and the visualisation and analysis of the data set.
Safe monitoring of the rectifier
Electrolysers are supplied with the necessary energy from a rectifier. A second rectifier, the polarising rectifier, is used to ramp up the system. Several manufacturers, including companies like Siemens Energy, constantly measure the current on their rectifiers with Muetec’s safe HVT transmitters. Current measurement is important as it can ensure that a minimum current is always running through the system. This prevents hydrogen ions from recombining in the electrolyser to form atoms, creating a risk of explosion.
Safe total voltage measurement
Both rectifier and electrolyser manufacturers regularly integrate safe total voltage transmitters into their setup. They measure the electrical characteristic at the handover point between rectifier and electrolyser, therefore between the work of two different suppliers. Usually, they generate a pre-alarm at 60 V, which is when touching the system becomes dangerous. The main alarm is normally set above the maximum voltage of the system, around 800 to 1200 V for a large AEL/AEM electrolyser, or less for a PEM or SOEC. The analogue output is used for a standardised measurement of the voltage, and MODBUS RTU for connection to the PLC.
Monitoring of fuel cells
What works well for electrolysers is also becoming common in fuel cells − the electrical monitoring of their total voltage. Multiple setups are available, depending on the technology used in the fuel cell, for example protecting the DC link and inverters against overvoltage or overload. Muetec’s high-voltage transmitters are also used to prevent a critical reverse-supply by feeding back some energy into the fuel cell in case of an error on the downstream side. These safety loops are becoming more and more common for large stationary fuel cells and for fuel cells on ships.
No accidents, and an efficient operation
The use of SIL2 transmitters for safe voltage and current monitoring brings multiple benefits. Making a design safe is now much easier for engineers, accidents are prevented, and data for efficient operation of the system is collected. Safe electrolysers, rectifiers and fuel cells are becoming common.
Waste To Energy thermal technologies DirectLogic Automation
Electrical Power & Protection
The vast quantities of waste produced around the world are a large and growing problem. Waste to Energy technology based on pyrolysis is a solution.
Read more...New enhanced Breaker Status and Communication Module Schneider Electric South Africa
Electrical Power & Protection
Schneider Electric has launched its new Breaker Status and Communication Module (BSCM) Modbus SL/ULP, which delivers enhanced performance, improved connectivity and simplified integration for power distribution systems.
Read more...Building green industries to scale green economies
Electrical Power & Protection
Africa is taking bold steps to build green industries across the continent. Namibia is a trailblazer in the hydrogen space, with up to five Final Investment Decisions scheduled to be made in 2025/2026 and is pioneering a world first for green industrialisation.
Read more...Easing the path for IPPs navigating South Africa’s energy regulations
Electrical Power & Protection
Independent Power Producers and developers venturing into South Africa’s renewable energy sector face a challenging regulatory landscape. SPS is a renewable energy asset management company that is actively expanding into the energy trading and wheeling market, which will enable businesses to buy and sell energy directly
Read more...How energy storage will make or break SA’s renewable transition
Electrical Power & Protection
Energy storage is no longer an add-on, but the foundation of a reliable, resilient and renewable energy system. As South Africa accelerates towards a greener future, storage innovation could determine the difference between progress and paralysis.
Read more...Condition-based maintenance can revolutionise business continuity Schneider Electric South Africa
Electrical Power & Protection
As businesses experience growing pressure to enhance operational efficiency and reduce downtime due to electrical failure, condition-based maintenance becomes essential for preventing unforeseen equipment breakdowns by assessing the real-time health of electrical systems.
Read more...Boiler selection for optimal thermal energy performance
Electrical Power & Protection
The changing world of boilers means companies wishing to improve their thermal energy efficiencies while containing costs and environmental impacts must make careful and informed decisions. AES’s rich pool of experience, ability to keep pace with new steam trends and technologies, and understanding of their clients’ production processes can assist clients to weigh up different options in a careful and informed manner.
Read more...Securing Africa’s energy future starts at home ACTOM Electrical Machines
Electrical Power & Protection
Africa’s energy demands are surging, but the current reliance on imported solar technology leaves the continent vulnerable. This is why the prospect of building inverters and lithium batteries locally, designed for South Africa’s specific needs, is so promising.
Read more...Dry-type transformers for Dutch intake substation
Electrical Power & Protection
A data centre in the Netherlands is the site of a recent innovation on the transformer landscape, where TMC Transformers has designed, manufactured and installed dry-type transformers in a large intake substation.
Read more...Generators: The muscle in the new energy mix WEG Africa
Electrical Power & Protection
Contrary to their reputation as noisy and dirty, generators are a key part of modern energy supplies. Generators are reliable electricity workhorses in times of need. But they are also becoming welcome additions to modern energy mixes through efficiency improvements, noise reduction and flexible design choices.
printer friendly version