Energy & grid analysers : Your questions, our answers.

A large proportion of energy consumption is attributable to industrial applications. The noticeable reduction in energy demand requires, among other things, optimised energy and power efficiency of supply grids and electrical installations. The dataTec portfolio offers an outstanding selection of power quality and energy measurement devices for system testing and power analysis as well as troubleshooting and documentation. This enables public utilities and industrial companies to record their energy data over a long period of time, make anomalies visible and take targeted measures for optimisation and maintenance.

The analysis of the supply grid forms the basis for optimising energy efficiency and energy consumption. Poor voltage quality in the power grid can result in increased energy costs, premature machine wear or even production downtimes. Harmonics in particular are an important cause of grid faults. Voltage fluctuations and transient events can also cause IT problems, increased lamp failures or burnt shield wires. 3-phase power meters with grid analysis function offer detailed grid monitoring by recording all relevant measured variables of a supply grid. This enables system operators to optimise the power supply to a machine or drive and avoid potential problems. Good grid quality is also a key aspect for regenerative load management in the smart grid.

Test and measurement technology helps to validate the operational safety, system performance, energy distribution or the reliability and control of power supply systems. This includes the following applications:

• Smart Grid (intelligent power grid): Smart grids are designed to ensure reliable electricity grids and integrate renewable energies. An intelligent monitoring and control system enables faults to be detected at an early stage and the energy distribution to be optimised.
• Analysis of power quality in grid applications: The grid power must be monitored precisely in order to avoid grid faults such as voltage dips and peaks, power interruptions or high-frequency noise.
• Condition monitoring of systems and machines: If mechanical faults in systems and machines are detected at an early stage, repair costs and potential production downtime can be minimised.
• Power conversion in power supply systems: Power converters must become increasingly intelligent and efficient in order to cope with the transition to renewable energies and meet the requirements of decentralised power grids.

In a smart grid, electricity generators, storage systems and consumers co-operate with each other. In combination with intelligent control of consumers (loads) by the power transmission and distribution grids, it is possible to ensure that only as much electricity is supplied as is currently being consumed. Power peaks or power fluctuations are thus balanced out according to the grid utilisation. Networking is achieved by using information and communication technologies and decentralised energy management.

Intelligent networking enables the efficient use and integration of renewable energies and the optimisation of the grid utilisation. For example, certain consumers in a grid, such as refrigerators, can be switched off briefly to minimise power peaks in order to cover the power consumption of the kitchen cookers at lunchtime. Alternatively, the intelligent control of washing machines and tumble dryers in the form of a night mode could utilise the industry's reduced energy requirements.

The development of smart grids is the result of decentralised electricity generation from wind power, photovoltaic and biogas plants as well as from conventional power plants. Electricity consumption can be regulated through technical requirements or through an intelligent tariff policy. This includes "smart metering", intelligent monitoring of the power consumed by individual consumers or households and the associated control of consumers within a household that can be switched off.

The energy consumption in a power grid can be recorded using energy and grid analysers. Energy and grid analysers monitor electricity grids by precisely measuring parameters such as voltage, current, frequency and power factor. They also focus on harmonic distortion that can indicate unwanted harmonic power oscillations. Energy and grid analysers focus on optimising energy efficiency in different environments. They measure the energy consumption of individual appliances, identify power losses, and also take into account transients, i.e. short-term current or voltage peaks. The detection of transients enables potential damage to be recognised at an early stage and countermeasures to be implemented. Grid and energy analysers play a crucial role in the proactive maintenance and optimisation of electrical systems. They also take the distortion factor into account to enable precise and reliable power evaluation. This contributes to cost-efficient operation and the responsible use of energy.

Electronic components and devices such as LEDs or mobile phones require a lower input voltage than the 230 V from the usual mains supply. For this purpose, appropriate ballasts convert the 230 V AC to voltages in the range of 5 to 15 V DC. The ballasts must fulfil the following functions: Current limiting, voltage reduction and rectification of the mains voltage. The ballasts and integrated buck converters result in the supply grid being subjected to various parasitic feedback that influence and "pollute" the grid. Typically, these are current harmonics which, in conjunction with the frequency-dependent line impedance, can lead to pollution of the mains voltage due to corresponding harmonics and cause corresponding interference with other loads.

An energy analyser or power logger measures and documents the power quality and performance data of systems, machines, or buildings. The aim is to optimise energy consumption and ensure trouble-free operation. Energy analysers provide a real-time snapshot of the energy consumption and, depending on the measurement function, also enable energy studies with corresponding logging.

A power quality analyser is used to continuously monitor and analyse single-phase and three-phase supply grids in order to identify faults that could cause damage to connected devices. It supports troubleshooting and logging and improves preventive maintenance. Power losses can also be identified to ensure compliance with supply requirements.

Power grids are subject to disturbances, e.g. voltage peaks, interruptions, or harmonics. The increasing influence of renewable energies, electric vehicles and grid-connected electricity storage systems also requires modern measurement technology in order to precisely monitor and analyse the grid quality. A power quality analyser enables special measurement applications in transmission and distribution grids to quantify power quality problems.

A power quality recorder enables the detailed recording of faults in the power supply with a long recording period of up to several months or even years. Trend analyses and class A grid monitoring ensure supply quality and reveal energy losses. Installation in the electrical system is carried out without interrupting the mains power supply.

Power analysers are used to evaluate electronic circuits, energy consumers or grid loads. There are different types of power analyser, including: 

3-phase power analysers allow the characteristics of a 1-phase or 3-phase system, e.g. a power supply grid, to be recorded in detail. A power analyser can be used to determine the power consumption, the amount of energy, the active, reactive and apparent power, the power factor, or the effectiveness of a power transmission. Basic parameters such as voltage, current, frequency, phase or harmonics are also recorded. Software-based detailed analyses enable energy flows to be validated and form the evaluation basis for preventive maintenance measures and process optimisation. Ideally, a power meter is equipped with additional grid analysis functions. 

A power analyser for electronic circuits provides precise insights into the power consumption (current consumption) of an electrical consumer. This allows the input and output power of a circuit to be measured, for example to determine the efficiency of the power transmission. In addition, the switch-on and switch-off characteristics can be analysed and basic parameters such as voltage, current, frequency, phase or harmonics can be measured.

Energy losses in buildings can be detected using a thermal imaging camera (thermography), among other things. Thermal imaging cameras can be used to efficiently localise temperature anomalies. They are used for building inspections, system maintenance or in HVAC systems. The cameras provide detailed images and precise measured values in real time. Thy function contact-free. This allows the condition of a building or system, e.g. electrical systems, to be examined and faults that could lead to mechanical faults or energy losses to be diagnosed. The visualisation of thermal anomalies forms the basis for further measurement analyses of the building condition.

Thermography can help in the search for heat losses in buildings. The most common instruments for evaluating heat losses are thermal imaging cameras (infrared cameras). Thermal imaging technology reveals missing, damaged or inadequate insulation, air leaks in the building shell, penetrating moisture and improperly executed construction work. Repairing this damage is often costly, so a thorough building analysis is essential. The measurements are contact-free and represent a non-destructive (non-invasive) test.

Defective components in electrical and mechanical systems represent a high safety risk and can lead to cost-intensive downtimes. For reliable electrical infrastructures in industrial and utility companies, thermal imaging technology (thermography) offers a particularly convenient and safe way of regularly checking system components and ensuring grid safety and efficiency. 

Portable thermal imaging cameras make it easy to localise temperature anomalies and visualise electrical asymmetries and energy losses. The cameras provide detailed images and precise measured values in real time. They are used without interfering with operation and at a safe distance from the system. In critical electrical installations, round-the-clock monitoring with permanently installed thermal imaging cameras can also be useful to ensure that no energy anomalies are missed and potential causes of failure are recognised in good time. By using thermal imaging cameras as part of regular inspection and maintenance measures, companies can maximise operational energy efficiency and avoid unplanned repairs and downtimes.

Leaks in compressed air systems can be localised using industrial sound cameras. Compressed air systems in industrial plants can be damaged by wear or inadequate maintenance. Leaks impair the energy and cost efficiency of the systems and may lead to quality problems or even production downtimes. Ultrasonic cameras make it easier for maintenance technicians to make leak detection part of their maintenance routine in order to detect and rectify compressed air leaks at an early stage. The acoustic image is superimposed on the visual image from such a digital camera in real time; leaks are immediately visible.

The regular inspection of high-voltage systems is mandatory for public utilities in order to detect electrical anomalies in switchgears, transformers, etc. and to maintain the power supply. Partial discharges indicate an insulation fault and can lead to equipment faults or serious accidents. Ultrasonic cameras provide precise sound images that allow different types of partial discharge to be immediately detected and interpreted.

Every electrical installation must be tested for electrical safety using a VDE tester before commissioning (initial test) and later at regular intervals (recurrent test) – for example as part of maintenance work. Installation testers and appliance testers are used for this type of VDE safety test. The prescribed measurements include low-impedance, insulation, earth resistance, site insulation, loop and mains impedance measurements. The measured values must then be documented in a legally secure manner.

PV systems should feed the generated electrical energy into the supply grid with maximum efficiency – even under varying conditions due to weather, load, or mechanical faults. With Maximum Power Point Tracking (MPPT), PV inverters continuously align the impedance of the solar cells with the maximum power point. Various PV testers are available for testing the function and performance of PV systems and PV inverters, including: 

• PV installation testers are used for standard-compliant installation and recurrent tests of grid-connected photovoltaic systems and to verify the specified performance data. PV testers simplify the work of installers on the roof. They support all measurements required to maintain, check, and certify the correct functioning of 1-phase and 3-phase photovoltaic systems. For example, the power output and temperature of the solar cells, the power output of an inverter or the solar irradiation (W/m2) can be measured. 
•  A PV power analyser or characteristic curve meter is used to test the performance and safety of PV systems and supports the preparation of reports during installation, commissioning, and maintenance. It enables the energy shares of the individual phases to be analysed precisely so that they are fed into the supply grid in the correct phase. Characteristic curve measurements on installed arrays allow the current power, the MPP (maximum power point), the short-circuit current and the open-circuit voltage, for example, to be displayed graphically. Thecurrent-voltage characteristics and power characteristics determined can be compared with the manufacturer's nominal specifications. This allows immediate conclusions to be drawn about the current quality condition of PV modules. A power analyser can also be used to measure the power input and output of single-phase and 3-phase PV inverters and compare them to each other in order to determine the power factor or efficiency. 
• Solar cells or modules represent a variable current/voltage source based on their characteristic I-U curves. In order to test the response and performance parameters of a PV inverter under realistic conditions, a power supply is required that can simulate the output characteristics of a solar cell. A PV simulator (also referred to as an SAS: Solar Array Simulator) is a programmable DC power supply that simulates the power output of a solar panel. User-defined I-U curves can be downloaded and automatic MPPT efficiency tests can be carried out with the appropriate software options. SAS are indispensable in the development of PV inverters by supporting the complex determination of MPPT algorithms. 
• Programmable AC/DC power supply units are available specifically for electronic inverter tests, which can simulate the characteristic curves of photovoltaic systems as well as the shading and different irradiation intensities of solar modules in order to simulate the resulting influence on inverters. A programmable power supply (power supply unit) is therefore an essential element in the test set-up for photovoltaic inverters. The current source enables the behaviour of the supply grid to be simulated via adjustable output powers. A bidirectional power supply combines a power source and electronic load in one device. Integrated test modes enable solar cell simulations to be carried out efficiently. 
• A grid simulator supports the pre-compliance testing and product verification of PV inverters. A wide range of test conditions can be simulated by programming grid characteristics, voltage distortions, frequency deviations, etc. 
• Thermal imaging cameras support the installation and maintenance of PV systems. For example, they can be used to detect interrupted connections in individual PV cells, broken glass, leaks, or short circuits.