VOLTAGE QUALITY

INTRODUCTION

Voltage quality refers to the quality of the electrical voltage available at a specific point in an electrical network. Electrical voltage quality is a comprehensive measure of how well the actual mains voltage supplied complies with standard specifications and how stable and interference-free it is when delivered to connected electrical consumers in terms of level, frequency, shape and reliability. 

Voltage quality also includes all deviations from an ideal sinusoidal voltage with constant frequency and amplitude. It is part of power quality. Across Europe, EN 50160 regulates how voltage level, frequency, harmonics and symmetry should look. Grid operators must comply with these standards; however, electricity consumers and producers may or must also actively influence voltage quality themselves by monitoring and optimising it, especially in the case of grid feed-in or grid feed-back. 

INTERNATIONALLY RELEVANT STANDARDS

WHY VOLTAGE QUALITY IS SO IMPORTANT

  • Prevents interference or failures in sensitive devices
  • Extends the service life of electrical systems
  • Supports the reliability and safety of the power supply
  • Important for the grid integration of renewable energies
  • Productivity & availability: In industry and data centres in particular, voltage fluctuations can cause serious damage and operational failures
  • Energy efficiency: Clean voltage reduces losses, thus saving energy and protecting components, devices and systems in electrical engineering systems

Measures to improve voltage quality in your applications with components, devices and systems from MBS-MP

MBS-MP offers you tailor-made solutions for your applications to minimise or eliminate the risks of malfunctions or failures in electrical operation and damage to connected systems, devices or components: 

  • Input and output chokes and filters
  • Fixed and adjustable transformers
  • Energy-saving systems with advanced voltage quality functions, including monitoring for continuous analysis of voltage quality
TYPICAL ASPECTS OF VOLTAGE QUALITY

VOLTAGE LEVEL

The effective value (e.g. 230 V ±10%) must be maintained in 95% of all 10-minute intervals (standard EN 50160). Deviations indicate grid instability and can damage connected consumers or lead to operational disruptions. 

FREQUENCY

Ideally 50 Hz in the European grid. Standard EN 50160 allows ±1% for 99.5% of the time (i.e. between 49.5 Hz and 50.5 Hz). 

WAVEFORM & HARMONICS

Deviations from the ideal sine wave due to harmonics place a strain on connected devices and are regulated by limit values (e.g. THD < 8%). 

VOLTAGE FLUCTUATIONS & FLICKER

Lights flicker when the voltage fluctuates, which is assessed using flicker curves. 

VOLTAGE DROPS (DIPS)

Short-term reduction in voltage, e.g. when large machines are switched on. 

OVERVOLTAGES (TRANSIENTS)

Short-term voltage peaks caused by switching operations or lightning strikes. 

INTERRUPTIONS (VOLTAGE DIPS, SHORT-TERM, LONG-TERM FAILURES)

Short-term interruptions (e.g. due to AWE) and outages reduce voltage quality and lead to damage and malfunctions. 

IMBALANCE / UNBALANCED LOAD

Uneven loads lead to uneven voltage in the phases of three-phase systems, which can cause problems. 

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