The importance of energy efficiency to heavy industry

The importance of energy efficiency to heavy industry

Capturing energy data at SKET Industriepark GmbH in Magdeburg

In addition to direct energy costs and effective capacity utilisation of power distribution systems and equipment, economic efficiency plays an important role at SKET Industriepark GmbH. In pursuit of continuous energy data capture, the company enlisted the support of Janitza electronics GmbH and HIT HIGH TECH Ingenieurgesellschaft mbH.

HIT HIGH TECH Ingenieurgesellschaft mbH with headquarters in Wilhelmshaven, was commissioned by SKET Industriepark GmbH (Magdeburg), a subsidiary of ENERCON in Aurich whose services include the main production of mechanical components for wind power plants (blades, towers, nacelles), to develop a system for standardised, low voltage-related billing of energy costs and for distribution of transformer power losses to corresponding cost centres.

Until now, it has only been possible to read off energy data from energy meters by hand. In order to optimise this time-consuming procedure, the energy meters have now been networked together in order to create an automated workflow.

As a result, a total of 77 measuring points at SKET Industriepark can now be queried electronically, with additional automatic monitoring of all key electrical parameters.

The shift to electronic data measurement and monitoring

With an existing Profibus fibre-optic ring being one of the largest load balancers on the site, there was little need for discussion about the type and nature of the data transmission. The only difficulty came from the relatively little space available in the distribution units, which meant that it was not possible to use every measuring device from the extensive range. In order to meet the limited spatial conditions, an especially compact measuring device had to be found for the individual outputs, and the UMG 103 universal measuring device from Janitza electronics GmbH was chosen. However, with an RS485/ Modbus interface, the UMG 103 was not entirely suitable owing to the need for data from the UMG 103s to be communicated over a Profibus connection. A solution was quickly found in Janitza‘s UMG 604EP device, installing it alongside the UMG 103. The UMG 604EP is a state-of-the-art measuring device with a sampling rate of 400 samples per period. In addition to an RS485 Modbus interface and RJ45 Ethernet connection, the UMG 604EP is also equipped with a Profibus interface.

In this setup, the UMG 103 operates as a data measuring point, capturing the data before transferring it to the UMG 604EP. The use of the UMG 604EP network analyser allows not only consumption data, but also key data relating to the currents, power and harmonics of the transformer stations to be displayed.

The UMG 604EP provides a range of features. In addition to reliable measurement, it is capable of simultaneous processing of 7 control programs.

For this, Janitza electronics GmbH has developed a special program (multitouch) for writing the variables of the slave measuring devices connected to the RS485 (in this case the UMG 103) to global variables in the UMG 604. Consequently, these devices can be used as a Profibus, Modbus/TCP or BACnet gateway.

Image 1: Graphic programming with GridVis®
Image 1: Graphic programming with GridVis®
Image 2: Network structure
Image 2: Network structure
Image 3: Profibus profile
Image 3: Profibus profile

Modbus Profibus gateway

The graphical programming makes it possible to establish a Modbus Profibus gateway. In the following examples, readouts are performed via Modbus slave measuring devices. The determined values are set on a Profibus profile (image 1). This program allows values from slave devices to be written to a Profibus profile via the gateway function, without a Profibus protocol. 

The data can then be captured via the connected S7 PLC. As part of the project, Wilhelmshaven-based HIT used its considerable expertise to help display the approx. 2000 data points from the measuring devices in a superordinate control software application. This involved configuring the corresponding Profibus profiles for the individual measuring devices, which are processed cyclically by the PLC (image 2).

The power analyser is capable of managing up to 255 Profibus profiles (16 profiles in the configuration). Each Profibus profile can contain a maximum of 128 data bytes. The first data byte of the PLC‘s output range always contains the profile number of the Profibus profile requested by the power analyser. To request a Profibus profile, the profile number must be written to the first byte of the PLC‘s output range (image 3). All system variables and global variables can be individually scaled and converted into one of the following formats: 8, 16, 32 bit integer with and without sign, 32 or 64 bit float format (big or little endian). (Image 4, 5 and 6)

Conclusion

The use of UMG 103 measuring devices and UMG 604EP network analysers has helped to produce an energy analysis based on the data acquired through automatic measurement data capture. The specially developed control software provides a basis for clear documentation and management of all available energy data. A continuous exchange of data, permanent monitoring and continuous data recording provide for a transparent and generally comprehensible energy balance. This in turn allows for straightforward identification of sources of errors and timely improvements to individual systems. These measures together help to ensure that energy consumption and energy costs are kept permanently in focus.

Image 4: Measured value view graphic
Image 4: Measured value view graphic
Image 5: Voltage and current trend logging
Image 5: Voltage and current trend logging
Image 6: Table view of active energy values
Image 6: Table view of active energy values

Advantages

  • Current overview of energy data

  • Basis for energy management systems in accordance with EN 50001

  • Monitoring of performance data of individual distribution units

  • Recording of events to improve system availability

  • Detailed display of various cost centres

Equipment used

Type/number of measuring devices

  • 15 x UMG 604EP
  • 62 x UMG103

Communication

  • Profibus to UMG 604EP
  • Modbus between UMG 604EP master and UMG 103 slave devices

Software

  • GridVis for power quality analysis
  • Win CC for visualisation and billing

Author

SKET Industriepark GmbH
www.sket-industriepark.de

HIT HIGH TEC Ingenieurgesellschaft mbH
www.hit-hightech.de

Company profile

Janitza® electronics GmbH

Janitza electronics GmbH is a German company and has been active for 50 years in the manufacturing of systems for efficient power application, energy measurement and cost savings. As a globally renowned manufacturer of network monitoring and energy management systems, digital integrated measurement devices, power factor controllers and compensation systems, the company stands for the highest quality standards and innovations. Products are manufactured according to leading-edge expertise with state-of-the-art production technology. At Janitza, quality management is an ongoing managerial task (e.g. ISO 9001). Comprehensive know-how, competent consultancy and concept generation, right through to the commissioning of tailored solutions, ensure fulfilment of customer wishes and requirements.

SKET Industriepark GmbH

SKET Industriepark GmbH unites efficient production and innovative industrial service to form an extraordinary combination of German skill and expertise. Its core areas include complex machine and system engineering, heavy steel construction and the production and processing of components for wind power plants. Jointly, these make SKET Industriepark part of a new industrial culture in Magdeburg, dedicated to the manufacture of state-of-the-art systems for the exploitation of renewable energy. Companies with operations at SKET Industriepark benefit from wholly synergy-based collaboration.

HIT HIGH TECH Ingenieurgesellschaft mbH

HIT HIGH TECH Ingenieurgesellschaft mbH is an international medium-sized company with headquarters in Wilhelmshaven. This experienced and forward-looking company provides planning for building services, including state-of-the-art building and industry automation. The engineering firm is recognised for its competence and reliability, and plans projects in the fields of electrical engineering, heating, air-conditioning and sanitary systems with high technical standards to meet the exacting requirements of its customers.

Services also include the compilation of expert reports and testing in accordance with the stipulations of the Association of Insurers (VdS). In addition to professional, timely execution, the company also prepares complete documentation. A team of highly-qualified and highly-motivated employees is on hand to provide customers with a reliable and professional service. Its friendly and customer-focused approach is complemented by a flexible and a safety-conscious way of working.

EMS energy management systems based on EN16001 / ISO 50001

Increasing energy prices, the discussion on stopping nuclear energy production entirely, dwindling fossil-based energy resources and increasing competitive pressure motivate politics and society to fundamentally reconsider the way we deal with energy.

Legal guidelines and regulations lend further impetus. Numerous investigations and studies (e.g. European Commission, DENA, Fraunhofer Institute) show that, in many cases, there is a considerable savings potential of up to 30 % and more.

EN 16001, a standard for energy management systems (EMS), was first released by the European Committee for Standardization (CEN) in July 2009. The general aim of this standard is to support organisations in the set-up of systems and processes to improve their energy efficiency. Systematic energy management leads to the reduction of energy expenditure, energy costs and greenhouse gas emissions.

The task of an energy management system is to determine the energy situation in the organisation, to redefine the energy policy of a company based on concrete data and to improve the energy efficiency. Furthermore, factors that influence energy consumption must be identified in order to continuously monitor and measure them. The energy manager of a company is responsible for pursuing the defined goals and continually improving the results achieved.

The decisive component in an energy management system is an effective and continuous energy controlling control circuit (Fig. 1). A control circuit of this type consists of the 4 stages: data acquisition, energy analysis, energy efficiency measures and inspection:

1) Continuous data acquisition and measurement:

A first step to escape the financial trap is the precise acquisition of all energy data, electrical and voltage quality parameters. First of all, the operating, consumption, and cost data (e.g. power, gas and district heating invoices) must be acquired and recorded by qualified personnel during the data acquisition phase. To make a detailed evaluation of an organisation and to create a basis for relevant energy efficiency measures, the energy flows must be further resolved from the supply side all the way down, which means major consumers or company units must also be measured and sub-measuring points are required. Because larger companies have many measuring points, often even hundreds of measuring points, automatic acquisition (EN16001, § A.5.1) of the energy consumers must be provided. Significant points for the configuration of such a data acquisition system include the decision about the data required (which electrical and energy parameters?), data resolution (different data requires different averaging times), query intervals and the communication architecture (e.g. TCP/IP (Ethernet), Bacnet, Profibus, Modbus …). Modern energy measuring technology (see UMG508, Fig. 2) provides the necessary transparency in the field of building energy supply. Continuous data acquisition is recommended in order to react speedily to changes in operation while also documenting the results achieved.

Via corresponding communication architectures (communication connection, Fig. 3), the acquired data is transmitted to a central location, stored centrally in high-performance databases and made available for further processing in an architecture that is as open as possible. Attention must also be paid to simple integration in higher-level systems, e.g. SCADA system, building control technology or PLC, as appropriate.

2) Energy analysis (target-actual comparison), provision of key figures, benchmarking:

The energy analysis is based on the data of the automatic measurement data acquisition system. The energy analysis provides the basis for the concrete goals of the enterprise with regard to energy consumption and energy cost reduction (e.g. 10 % energy savings a year). In addition, the energy analysis results are also the significant starting point for an ABC analysis of the consumers, the development of a catalogue of measures, evaluation of specific measures, prioritisation of the energy efficiency measures and creation of a detailed plan of measures.

3) Planning and design of energy efficiency measures:

The results of the energy analysis flow into the planning of measures for reducing the energy consumption and energy costs. The measures can be divided into four groups:

  • Planning: Examination of energy use, optimisation of operating times, machines with high efficiency, peak load optimisation, heat recovery…
  • Organisational measures: Area of acquisition (e.g. putting emphasis on the life cycle costs), changes to the workflow, in the area of regulation/control, the conduct of employees, during maintenance and repair, training and motivation
  • Technical measures: Use of more energy efficient motors (more than 95 % of the life cycle costs of an electrical drive are energy costs), changing to frequency inverters, use of heat recovery, leakage reduction in the compressed air network, optimisation of the regulation and control of systems, optimisation of steam generation, intelligent use of peak load optimisation/energy storage…
  • Load management: Load management constitutes a special measure. Optimisation of the power load profile does not primarily bring energy savings but, depending on the power supplier contract, leads to substantial cost savings. This measure also stabilises the energy supply.

4) Checking and correction:

What is the point of an energy management system?

  • The identification of "energy wasters" and introduction of measures results in the reduction of power and energy costs (kWh, peak load costs, reactive power costs)
  • Reduction of climate killing carbon dioxide (Green IT, Zero carbon offices, Kyoto …)
  • Stabilisation of processes (improvement of the power quality)
  • Maintenance costs are lowered by pro-active maintenance and reduced stress factors
  • Power failures, e.g. due to harmonic oscillations, voltage drops or transients, are avoided
  • Greater awareness of employees with regard to energy savings and climate protection
  • Fulfilment of legal framework guidelines, energy tax reduction
  • Cost centre management enables consumption-oriented cost allocation
  • Environmental protection and corporate image cultivation

The power bill is usually the gauge for the cost calculation of operational plants, buildings or infrastructural facilities. However, this bill is only the visible part of sometimes much higher costs, taking a "dirty" and unreliable energy supply into account. Next to the direct electricity costs, the effective capacity utilisation of energy distribution systems and facilities as well as a reliable energy supply also play an important role in economic efficiency. As these costs are not so obvious, they are also referred to "hidden costs".

With an integrated, integral energy management system, you can also centrally monitor and compare (benchmark) branches at various geographical locations, for example. The power consumption, reactive power monitoring, water and gas consumption, the availability of electrical energy and the power quality can be collected, evaluated and analysed in the database at company headquarters. This can also increase energy efficiency as saving potentials are revealed by cost comparison.

Practically at the push of a button, the relevant software can be used to prepare the various data and create statistics and tables in the desired format, which are then made available to the financial controlling, the energy manager, the purchasing department or facility management. In the area of property management, this also means an improvement of the preciseness of power consumption accounts and convenient, automated, customer-specific accounting (cost centre management), for example.

End-to-end energy management systems create network transparency on the various network levels, which allows the identification of possible "sinners", uncovering inefficient processes and initiation of corresponding energy efficiency measures. Many energy efficiency measures can be achieved with low financial investments. And even with real capital investment, a return of investment can often be expected within 6s–18 months.

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