Modern electrical equipment demands Power Quality, which imposes stringent demands on voltage stability and power quality. The power network has to be free from harmonics and other electrical disturbances.

Multiple Frequency Currents and Voltages existing in the Power System, which are integral multiples of fundamental 50 Hz waveform, are called Harmonics, or “dirty power”. Odd positive and negative sequence harmonic currents, are generated by three-phase full wave, non-linear loads, which are connected to a three-phase, three or four-wire distribution system. Odd positive, negative and zero sequence harmonic currents are generated by single-phase, full-wave non-linear loads which are connected phase to neutral in a three phase, four wire distribution system.

Harmonic Currents produce Harmonic Voltage distortion also depending on system impedance. The major contributors of Dirty power (Harmonics) are:

• Variable speed drives
• Power rectifiers
• UPS, SMPS of computers and the like, LAN/ Servers, printers
• Photo copiers, Facsimiles,
• Electronic ballasts
• Virtually all-low power electronic devices
• Saturated Cored Transformers, inductors and chokes.

Zero sequence harmonic phase currents are in-phase unlike positive and negative sequence harmonic currents displaced by 120°. Arithmetic combination of these Zero sequence currents happens at Distribution transformer’s terminal and return to their source via the neutral conductor. In certain cases, the resulting neutral current can exceed twice the phase current. This can be detrimental to the distribution system and the transformer, apart from increasing the system losses appreciably.

Effects of Harmonics:

• Increased losses, e.g. machines will operate at increased temperature and can be overheated
• Resonance problems between the inductive and capacitive parts of the power network
• Malfunctioning of control systems since electronic meters, relays, etc. are matched to the fundamental frequency
• Overloading of capacitors, leading to malfunctioning and premature aging
• Interference with telecommunications and computers
• Disturbances in ripple control systems
• High currents in neutral conductors.

Solution to Harmonic Problems

Solutions to Harmonic Problems are available as custom-made products from the Dynaspede Power Systems’ product range. A Passive Harmonic Filter called `ESCOFILTER’ is available for a wide range of applications. Both Tuned and De-tuned Filters are available .Zero sequence, inductive filters are also designed, manufactured and supplied, according to customer requirements.

By installing Harmonic Suppression Systems, you can:

• Filter Harmonics in the system
• Achieve higher power factor, improved voltage stability and network losses, recovering up to 30% of wasted system electrical capacity
• Avoid resonance problems and amplification of electrical disturbances
• Lengthen the life of your equipment as the “clean” network imposes much less strain on it
• Lower the maintenance cost and lower the cost for replacing worn-out equipment
• Eliminate expensive electrical system downtime

Escofilter Features:

• Single or multistage as required
• Manual switching for single stage and Automatic Switching for multistage applications
• Single-tuned, Multi-tuned and High-pass Filter Banks available
• Bank Voltages from 415 Volts to 33 Kv
• Reactive power ratings from 10KVAR to 1000 KVAR (L.V)
• Up to 10 MVAR in Medium Voltages
• Fully coordinated protection package engineered to meet customer requirements and performance specifications
• Rugged capacitors
• Film & Foil Capacitors for the Medium Voltages and Heavy duty capacitors for the L.V systems.(up to 690 volts).

Product Specifications

Our Filter Bank incorporating heavy duty capacitors has low loss Polypropylene Film, discharge Resistors and is leak-free. The design can withstand high inrush currents, hence trouble-free.

ESCOFILTER has 1/3 phase iron-core dry type reactors, Copper windings with Class F or Class H insulation. It is designed for 50° C rise over the ambient temperature. These are shunt Filters normally used for shifting natural/resonant frequency of electrical system under harmonic influence and improves power factor for fundamental frequency and reduce distortion levels based on individual system characteristic and filter design.

Type of Filters:
Classification of Harmonic Filter is based on its Filtering capability by its tuning class, which in turn is based on the Absorption duty cycle of Harmonic Filters as well as savings. Dynaspede offers:

• Tuned Filter
• De-tuned Filter
• Zero Sequence Filters

Specifications and Design of ESCOFILTER and its components are based on the following variables.

• System Short Circuit Level
• Existence of other Harmonic Filter and Shunt Capacitor Banks
• Rating and type of Non-linear load to be filtered
• Plan for future system expansion
• Ambient voltage distortion.
• Harmonic Spectrum, THD levels and TDD level.
  

There are several satisfactorily working ESCOFILTERS in India and other countries, for different applications.