Electricity is perhaps the most essential raw material used by commerce and industry today. The electricity produced in power plants is circulated through the electricity transmission and distribution networks and it is supplied/delivered to consumers; the quality of electricity (known as «Power Quality») is one of the important factors that determine the economic efﬁciency of both consumers and electrical networks.
Electrical devices are designed to work in distributing systems deﬁned by set nominal values in terms of voltage and frequency (for example, 400V at 50Hz).
In actual fact, electric energy distribution might not ensure the stability of said nominal parameters. Voltage in particular can vary even considerably in relation to the nominal value. These variation can cause undesired and potentially dangerous conditions for the users.
Voltage “ﬂuctuations’ can be ‘fast’ and waste themselves away in a few milliseconds (for example, distribution lines hit by lightning) or ‘slow’, with duration that can last several seconds, minutes or even hours depending on the cause.
Slow ﬂuctuations can be generated by increased voltage level (‘surge’ due to poor MV regulation at distribution level, disconnection of large loads, overvoltage at generators output, etc) or – more frequently – by decreased voltage level (‘sags’ due to connection of large loads, motor startup, undersized distribution lines, faults to ground, poor MV voltage regulation, etc).
In case of voltage variation, the voltage stabilizer is the solution that guarantees for the best cost/beneﬁt ratio.
The continuous availability of stable voltage supply independently from input ﬂuctuation is very often a key feature to ensure efﬁciency and reliability for the User.
Reduced productivity, data loss, security failure, machine faults, inaccurate information and domestic inconveniences are only a few examples of potential problems caused by unsteady supply. Obviously, all that results in higher managing cost.
The voltage stabilizer has proven to be an effective solution able to prevent potentially dangerous situations created by input voltage instability.
The main application ﬁelds where devices sensitive to voltage variations can be used include:
– Industrial sector: oil & gas, laser cutting, water shearing, tobacco industry, textile industry, galvanic processes, machinery in general.
– Food & Beverage: industry, intensive breeding, food processing, packaging, bottling.
– Tertiary & servicing: banks, hotels & tourist resorts, data centre, laboratories, small businesses, private users.
– Telecommunications: TV/Radio stations, telecom networks.
– Public sector: hospitals, public ofﬁces & institutions.
– Renewable sources: solar and wind farms.
In all these applications, voltage ﬂuctuation, even though within the tolerance admitted by the Standards, can generate operating issues. In that case, devices particularly sensitive can show errors or malfunctions beyond the acceptable limit.
Typical situations where voltage can be subject to ﬂuctuation beyond the admitted tolerance are:
– Loads supplied by weak or undersized distributing lines (rural areas or locations supplied by long distributing lines such as breeding farms, tourist resorts, hotels, etc).
– Users located near distributing station and therefore subject to voltage increase.
– Private premises with high power installations (swimming pool pumps, big chillers, special lighting systems, lifts) and/or particularly voltage sensitive loads (high power consumer electronics, etc.).
– Loads located near large industrial plants where individual high power devices (MV motors) can induce voltage reduction at startup.
– Island operating loads (ships, offshore rigs, loads not connected to the public grid).
In comparison to other types of equipment, the voltage stabilser offers a number of advantages that very often make it the optimum solution:
– Usually lower price.
– High output voltage stability guaranteed even for wide input ﬂuctuation.
– Absence of introduced harmonic distortion.
– Robust and reliable construction, allowing for use in hard environments.
– Overload capability up to twice the rated current (max 2 mins).
– No concerns in terms of storage, transportation, maintenance and disposal due to the fact that batteries are not used.
– Smooth and reliable regulation of the load voltage ensuring a ±0.5% accuracy even with important input voltage variation.
– High efﬁciency.
– High inrush current withstand capability.
– Reduced dimension, simple to run, ‘plug&play’ operating mode.
The static stabilizer is used when the correction speed represents the critical issue (for example, computers, laboratory equipment, measuring benches and medical instrumentation). This kind of stabilizer has correction time of 3 milliseconds for full regulation as compared to electro-mechanical stabilizer correction time of 10-50 milliseconds (depends on the model) per volt.