Best practice case study: Avoiding system overload

Display of all key energy data

Users of the TQ-Systems energy data management system can see all sources of electricity and electrical loads at a glance. (Copyright: TQ-Systems)

Avoiding system overload

Dynamic load management reduces industrial energy costs

Modern industrial buildings may have increased load management requirements as a result of their greater use of volatile renewable energy, and of the additional energy they need due to the expansion of e-mobility. An intelligent, automated energy management system prevents unnecessary load peaks and ultimately saves money.

Anyone who has ever met the cycling robot RoCy, used the reading light on board an airplane or bought a ticket at a train station has knowingly or unknowingly come into contact with technology developed by the TQ-Systems Group . TQ-Systems is a leading German technology company providing electronics engineering and manufacturing services (E²MS). It also develops its own products, such as embedded modules or drive and automation solutions. As a result, it is represented in virtually all growing technological industries, including e-mobility, robotics, medical engineering and aerospace. The company, which employs 1,700 people across 14 locations, also counts energy management and building automation as part of its portfolio.

It began gradually implementing its own energy management system (EMS) at its headquarters in Gut Delling, Seefeld, to the east of Munich, in 2016. With around 600 employees, the site is the largest in the TQ-Group and comprises production lines featuring equipment such as soldering furnaces and pick-and-place machines, as well as administrative offices. The EMS was finally completed and certified to ISO 50001 in summer 2018. First of all, this means that the company has fulfilled the legal obligation for non-SMEs to be certified. In addition, by using sustainable measures and state-of-the-art technology to optimize its own energy demand and protect the climate, TQ-Systems is living up to its role as a pioneering technology company.

Managing energy using products developed in-house

To record its power consumption, TQ-Systems fitted more than seventy EM 300  energy managers, including sensors, into the electrical sub-distribution units in the building and integrated them into a separate TCP network. The company can use the smart meters to selectively measure and trace around 80% of its total electricity demand. At present, the system only measures electricity consumption. However, it has been designed to allow modular expansion over the next few years so that other energy resources can be assessed in the future – for example gas, water and oil consumption as well as heating and cooling energy requirements.

A software program makes it possible to visually represent load profiles, time series analyses, load behavior and energy consumption values as well as to analyze the results. However, TQ-Systems wanted to do much more than simply measure and analyze power consumption. By integrating an intelligent load management solution, its aim was to avoid load peaks and reduce energy costs. By using its own demand-side management system (DM100), the company has also integrated charging stations into its energy automation solution, in addition to the electrical loads on its production lines such as soldering furnaces and cooling units.

Avoiding expensive load peaks

Together with the EM 300  energy managers, the demand-side management system (DSM) records current levels of consumption and limits the electricity demand in terms of the connected load of the transformer (overload protection), the connected load of the individual sub-distribution units and the supply rate contractually agreed with the utility company. It also integrates battery systems and ensures individual units and processes are suitably protected. To optimize energy management further, load peaks are recorded and all process and switching conditions are visualized.

Taking the real power measured as a basis, the software module, which synchronizes with the utility company’s power meter, calculates the mean power value and predicts the level of consumption expected for the current metering period. If this is anticipated to exceed the supply rate, electrical loads will be gradually turned off, their power consumption will be reduced or, if possible, power generation units will be put into operation. The order in which the various loads are to be turned off or generators are to be turned on, as well as minimum switching times and any restricted periods, can be programmed individually. The intelligent load management system also allows for the use of variable electricity tariffs.

Hunting down power guzzlers

The comprehensive collection of consumption data allowed TQ-Systems to uncover a number of “power guzzlers” and irregularities. For example, the cooling unit exhibited abnormal behavior in terms of how it turned itself on and off and its frequent tap changing. In addition, the way in which the soldering furnaces were switched on at the same time resulted in unnecessary load peaks. Once this was discovered, the cooling unit’s control parameters were optimized in terms of cold water demand; the soldering furnaces are no longer turned on simultaneously, but are automatically started up one after the other. Thanks to the DSM, TQ-Systems has already been able to decrease its annual electricity consumption by 8% and extend both the maintenance cycles and the useful life of its machinery. What’s more, the company has set itself the target of reducing its load peaks from 843 kW to 761 kW in the future in order to cut energy costs further. In order to make full use of its available capacities, it intends to accelerate the electrification of its fleet of cars. For example, it is planning to implement various algorithms capable of prioritizing the charging of electric cars depending on the users – i.e. customers, sales representatives or employees – and of keeping charging power within certain limits.

By Simone Pabst

More information: TQ-Systems

TQ-Systems is an exhibitor at EM-Power 2019, booth C4.180