Voltage optimization
Reduce energy costs through optimized voltage
For loads such as conventional, i.e. non-frequency-controlled motors, heaters or lighting, the energy consumption is influenced, among other things, by the voltage with which the devices are supplied. If such a device is supplied with a higher voltage than necessary, it consumes more energy than required.
Systematically optimising or reducing the voltage in public grids has been practised in North America for decades in order to reduce energy consumption and the associated losses and to lower peak demand. This method, called 'Conservation Voltage Reduction' (CVR), is also used successfully by grid operators such as ENWL in the UK. This energy-saving measure can also be applied in industrial distribution networks.
Distribution transformers with on-load tap-changers ensure that the voltage is always regulated to the consumption-optimised level. The ECOTAP® VPD® on-load tap-changer offers the necessary wide control range with simultaneous fine individual steps. Installed in transformers of various power classes (manufacturer-independent up to approx. 36kV as well as 8,000kVA), it is the standard for all network types. Due to its compact dimensions, regulated distribution transformers have a similar footprint as unregulated ones. In addition, this solution is maintenance-free and sustainable.
Figure: Functional principle of the local network transformer with on-load tap-changer
With unregulated or rigid distribution transformers, voltage band violations can occur when using the CVR method:
- If the output voltage is lowered at the HV/MV transformer, violations of the lower voltage band can occur at high loads due to the voltage drop at the end of the line, since rigid MV/LV transformers virtually pass on the lower voltages; conversely, overvoltages can occur with volatile feeders and reversed load flow.
- At the same time, violations of the upper voltage band can occur with consumers close to the substation. If the transformation ratio of rigid MV/LV transformers were geared to this, problems could again arise with volatile feeders and reversed load flow.
In both cases, the use of regulated distribution transformers (so-called VRDTs) solves these problems.
- If VRDT's are finally used distributed over the MV line at critical points, then the output voltage of the MV/LV transformer can be lowered even further. Possible violations of the voltage band are avoided by skilful use of the VRDTs while the voltage for the consumers is optimised.
The British grid operator Electricity North West (ENWL) has investigated innovative technologies for optimising the supply voltage in a four-year research project. The goal was to obtain a monitored and actively optimised low-voltage grid, while at the same time increasing the integration of renewable energies. During the test run, which lasted several years, it was possible to save up to 8.5% of the energy consumption and reduce losses by 8% by reducing the voltage by 5-8% using the CVR methodology. The Voltage Regulating Distribution Transformers (VRDTs) made the main contribution to this.
Image: VRDT in use at the distribution grid operator ENWL
Your advantages:
-
Large control range with 9 or 17 on-load tap-changer positions with simultaneous fine gradation of the switching steps
-
Can be used in any existing local network station and even on mast installations due to its very compact dimensions
-
Low investment and operating costs due to freedom from maintenance and long service life
-
Receipt of valuable additional information through digital connection with simultaneous possibility of actively influencing the network events
Worldwide deliveries
Transformer Manufacturers
On-Load Tap-Changers
Operators
