Performance Monitoring System

Goals of the energy monitoring are:

• Reduction of power consumption
• Analysis and optimization of production facilities
• Comparison of production-related plants
• Cost accounting or costing
• Controlling
• Optimization of energy purchasing

By means of energy monitoring, we are continuing to develop the subject »condition monitoring« for industrial applications. From the recorded current and voltage curves, features can be extracted with newly developed algorithms that give indications of imminent defects or malfunctions. A downstream evaluation with the help of these criteria informs the operators of possible problems in the production. The goal is to perform condition-based maintenance with this information, rather than working on a rigid schedule that does not take into account the real state of the machine. This should minimize downtimes in the production area, plant repairs or rejects of the produced goods.

Many energy-intensive companies must be certified to the ISO 50001 energy management standard and demonstrate continued savings to continue to receive tax relief on energy purchases. For existing systems, retrofitting with measuring equipment is very difficult to perform due to space constraints. It lends itself to a mounting in the electrical distribution cabinets. Current solutions which are mostly based on magnetoresistive measuring methods are relatively expensive, large, have no integrated evaluation and output the measured values ​​by means of interference-prone analog signals.

The energy measuring system developed by Fraunhofer IIS together with an industrial user and marketer offers a variety of unique selling points as a flexible monitoring system. It consists of bus-capable measuring sensors and an evaluation unit. All components are designed to save space and can be installed in existing distribution cabinets without interrupting ongoing operation. The integration of voltage measurement and current measurement simplifies the installation effort. The assembly is carried out by pressing the measuring sensor onto the line to be monitored.

The core component of the system is the measuring sensor:

• Board consists of a rigid part and a flexible conductor
• Flip-chip mounting of the sensors
• Plastic housing
• Mandrel for contacting the conductor
• Spring for the long-term stability of the connection
• VDE certification

The voltage is measured by direct contact with the conductor during assembly. The voltage values ​​are picked off via a pin and digitized and further processed using the analog-to-digital converter of the microcontroller on the measuring sensor. The current measurement is performed contactless by highly integrated Hall sensors, which are arranged in a ring around the current-carrying conductor. The individual measuring sensors are connected to an evaluation unit via a bus cabling. It has the task of combining several sensors into a 3-phase measurement and logically assigning the sensors to a system. A higher-level automation or evaluation unit can query all system-related measured values ​​to the second via an Ethernet interface or a Modbus RTU interface. In addition, the evaluation unit stores historical measurement data in its internal FLASH memory. For example, the measured data is available decentrally for up to three days and can be queried via the integrated FTP server.