Protecting from Voltage Sags or Dips Whilst Ensuring High-Quality Power to Sensitive Loads

Voltage sags or dips are constant issues even in developed countries with modern power networks. Although outages may not be frequent, the voltage issues caused by network faults, weather, or other power cable events are ubiquitous. With the advent of automation in modern industrial set-ups, the sensitivity of process to power quality events is growing. In fact, even a short event can halt processes unexpectedly and this in turn would lead to production shortages, wastage and product damage.

Voltage is not properly regulated in developing areas or countries with a weak power supply. Without proper voltage, it is not possible to operate the process reliably. In situations where the voltage is unbalanced or low, overheating of motors presents a major concern.

In industrial parks, a number of industrial sites are located together. In such scenarios, the clustering of these power utilization means if a particular user disturbs the utility voltage it will impact other industries. Faults or weather events in other parts of the utility network can lead to voltage sags well below the nominal value, and stay there for a number of seconds. Such fluctuations can stop the operation of sensitive production equipment.

If a manufacturing line stops, it has to be resumed and this can be a complex and costly process. Any damage to the equipment induced by power quality events can prove even more expensive. Moreover, equipment may largely depend on a steady power supply to give a quality end product. Hence, it would be best for companies to invest in equipment so that the risk of uncertain power supply is eliminated and at the same time a steady supply of clean and high-quality power is ensured.

The PCS100 AVC Product

The PCS100 Active Voltage Conditioner (AVC) products (Figure 1) developed by ABB perfectly meet these requirements. They are specifically designed to protect industries from voltage events, thus enabling them to carry out their operations uninterruptedly.

ABB’s PCS100 AVC products

Figure 1. ABB’s PCS100 AVC products protect from voltage sags or dips and ensure a supply of high-quality power to sensitive loads.

ABB stocks a wide range of power protection products and among these the PCS100 AVC product is quite unique. It is specifically designed for commercial and industrial applications and responds quickly to voltage surges and sags, corrects for voltage imbalance, and removes voltage flicker. The PCS100 AVC system includes two converters, which are not on the current path between the utility and the sensitive load. As an alternative, the corrective voltage injection can be obtained with a transformer winding between the load and the utility. This configuration presents an effective method for voltage correction.

The PCS100 AVC system eliminates the use of batteries and draws the extra energy needed to make up the correction voltage from the utility supply. This means, the cost of ownership for PCS100 AVC systems is lower as there are no maintenance costs which are commonly associated with batteries. In addition, a redundant bypass system integrated in the PCS100 AVC ensures that the load is constantly supplied from the utility in the event of a fault with the AVC. The PCS100 AVC comes with ratings ranging from 150kVA to 3MVA, realized in a low-voltage switchgear cabinet. The system provides high scalability in terms of power and voltage level as well as online voltage regulation in less than two milliseconds. It includes an advanced control software, a reliable converter platform, and offers 99% efficiency.

The PCS100 AVC product range includes two models: the PCS100 AVC- 20 for constant voltage regulation and the PCS100 AVC-40 for sag correction. Each system is designed to resolve different types of power supply issues.

PCS100 AVC-20 for Continuous Voltage Regulation

The PCS100 AVC-20 product is rated at up to 3MVA and ensures steady voltage regulation to 100% for voltage variations of ±20% of the mains voltage. The system also removes imbalances from the supply voltage.

In cases where there are higher voltage variations, the PCS100 AVC-20 will carry out a partial correction with 20% voltage injection, that is, for voltage variations of -30% of the mains voltage, it corrects to 90% of the nominal voltage respectively, maintaining voltage levels within normal specifications of most electrical devices.

PCS100 AVC-40 for Sag Correction

The PCS100 AVC-40 is designed to respond to voltage swells or sags quickly and efficiently and can inject up to 40% voltage correction. In situations where a facility experiences a voltage sag to 60% of nominal voltage, the PCS100 AVC-40 system would increase the voltage back to 100%. Thus, equipment would not trip and lights would not dip, thereby preventing higher operational costs. Performance is dramatically improved in scenarios where single phase sags occur. In addition, voltage sags down to 45% of the nominal voltage can be completely corrected.

If there is deeper voltage sags, the PCS100 AVC-40 system carries out a partial correction, which prevents loads tripping. It also corrects voltage variations of ±10% of nominal and removes flicker and imbalances from the supply voltage. The PCS100 AVC-40 product is rated from 150kVA to 1.8 MVA and is available for 220, 400 and 480VAC. Special powers and voltages up to a number of MVA are available as custom designs.

Common Features

Common features of the PCS100 AVC- 20 and PCS100 AVC-40 models are as follows:

  • High reliability: Built-in bypass, industrial-grade overloads and fault capacity
  • Compact dimensions: Make it possible to install the systems in tight places
  • Low total cost of ownership: High efficiency, no energy storage, and low maintenance

Both PCS100 AVC-20 and AVC-40 systems come with a large LCD touch screen, which not only makes it easy to operate the devices but also allows access to detailed event logs. In addition, a built-in Web server enables remote access and allows emails to be sent to those concerned in the event of power failure.


Factories with advanced equipment are exposed to risks of uncertain power supply such as surges and sags. By installing the PCS100 AVC systems from ABB, companies can significantly reduce downtime and avoid production shortages, product damage and wastage.

About ABB Power Conditioning - Discrete Automation and Motion Division

ABB is a leading supplier of UPS and power conditioning products – ABB's PCS100 portfolio is a unique line up of low and medium voltage power conversion technology. The PCS100 power converters demonstrate highly reliable and cost-effective performance. With the PCS100 product portfolio, ABB offer efficient power conversion solutions that are specifically designed to solve power quality problems and stabilize networks. Covering applications from data centers through to complete industrial plant protection, microgrid systems and shore-to-ship supply, ABB have the power conversion technology for every need. Starting from a few kVA to many MVA and a wide range of supply voltages. ABB has installed more than 900 MW of power conditioning solutions worldwide. It’s business as usual with ABB Power Protection

This information has been sourced, reviewed and adapted from materials provided by ABB Power Conditioning - Discrete Automation and Motion Division.

For more information on this source, please visit ABB Power Conditioning - Discrete Automation and Motion Division.


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