ESM 7 Investigation of network symmetry and quality

Use of many electronic appliances, energy saving lamps, uninterruptible power supplies (UPS) and regenerative energies is posing new problems to electricity providers. For this reason it is important to plan the loads on wiring logically and properly. Symmetric loading of mains networks should be one aspect taken into consideration for any wiring installation. In addition, the wide variety of electronic components is causing more and more disturbance to mains symmetry and affecting the quality of the network. This experiment board is intended to convey the key aspects regarding use of switched-mode power supplies, incandescent or energy saving bulbs as they affect mains quality. All the investigations are carried out at mains voltages of 230/400 V and 50 Hz frequency. This ensures that all the results can be reproduced on a real mains network.

Training contents:

• Familiarisation with single-phase and multi-phase systems
• Relationships between current, voltage and power in coupled systems
• Ways of depicting coupled systems, e.g. vector diagrams
• Load on the neutral conductor due to symmetric and asymmetric loads
• Effects of disturbances on network symmetry
• Evaluation of network disturbances via network analysis
• Investigation of neutral loading by the third harmonic
• Design and effects of various rectifier circuits