MSB (Main Distribution Switchboard) is a kind of electrical cabinet installed right after the low voltage substations (from 15kV down to 380VAC), the major function of MSB cabinets is connect & disconnect, safety protection for electrical systems. Rated current can reach approximately 6300A.
STPower - Cable ladder is also known as electric ladder, applied to install electrical wires and cables in factories, apartments, buildings ... is the bearing structure of the system.
Product new: STPower - Distributors and Agents for Electrical products ABB in the central of Vietnam
Cubiele Switchboards which are designed and manufactured in accordance with strict quality management, high stability and secure operation has been widely used in power stations, power distribution station in power companies, industrial parks, residential quarters and factories...
Breakers & Switches are designed for flexibility and reliable performance in a wide variety of applications: power distribution for residential and industrial buildings, HVAC, water pumping stations, data centers
Cable tray (trunking) is the conduit for the installation of wires and cables in factories, apartment buildings, office buildings
Cubiele Switchboards which are designed and manufactured in accordance with strict quality management, high stability and secure operation has been widely used in power stations, power distribution station in power companies, industrial parks, residential quarters and factories...Harmonic is a form of unwanted noise, directly affect the quality of power and should be paying attention to harmonic voltage or current enables higher levels.
Harmonics are voltage or electric current is sinusoidal frequency multiples of industrial frequency (fundamental frequency), by the presence of non-linear loads in the grid. For example, current harmonic frequency is 250Hz on the grid harmonic 50HZ 5.
Figure 1: The waveforms and harmonics level
Harmonics makes cable overheating, damaged insulation. Overheating engine noise and the vibration of torque on the rotor leads to mechanical resonance and vibration. Capacitor overheating and in the majority of cases can lead to destruction of dielectrics. The protective device may be an error, impact; measuring equipment for wrong results; the control circuit in line to run automatically wrong or disturbance.
There are many sources of harmonics in industrial systems is the non-linear loads such as variable frequency motor, electric drive systems, arc furnaces, electric arc welding machines, transformers, inverters, computer and other electronic devices.
To reduce the effects of harmonics in power distribution systems, in Article 7 of Circular 39/2015 / TT-BCT dated 18/11/2015 of the Ministry of Industry and Trade provisions: total harmonic distortion voltage at every point medium and low voltage connections can not exceed the following limits:
• Total harmonic distortion: ≤ 6.5%
• Individual Deformation: ≤ 3.0%
For the customer's device (device connection) also provides for the following harmonics in Article 32 of Circular 39:
• Level medium voltage and low voltage have less than 50 kW power: The value of harmonic currents in excess of 20% high load currents;
• The total current harmonic distortion is measured according to the standards IEC1000-4-7, lasting at least 24 hours with 10 minutes 01 times cycle. At least 06 months from the time of detection of the client device does not achieve the specified value, the customer must apply the corrective measures to achieve the value of total harmonic distortion of current limits phep.May measuring power quality analysis of Hioki PW3198 help measure, analyze and record the harmonic problems.
PW3198 can measure all the electric current waveform, voltage, power, harmonics and recorded the events of electricity (brownouts, over voltage, voltage flicker, instantaneous voltage, current shock, unbalanced voltage / current, higher harmonic) simultaneously at a time makes it easy to detect and handle problems quickly occur. PW3198 comply with international standards IEC61000-4-30 Edition 2 Class A requirements for measuring power quality parameters and accuracy.
• Measure the RMS value and phase angle of the harmonic from grade 0 to grade 50, displayed as numbers or graphs. PW3198 can measure the ratio of the total harmonic distortion (THD) of voltage and current.
• Measure and record the RMS value of the harmonic waveform high voltage / current frequency from 2kHz to 80kHz, the cause of the error and equipment damage.
• Measure the difference between voltage harmonic phase angle and harmonic current phase angle for each phase and the sum of the phase value. Overall value helps determine the direction of harmonics is downstream (from the net on the load) or way up (from the load to the grid). If the total phase angle difference is from -90 ° to + 90 °, the harmonics are going down, if total deviation from -180 ° phase angle is -90 ° to + 90 ° or 180 ° to the harmonics are going up .
Quickview:
Circular 39/2015 / TT-BCT dated 18/11/2015 of the Ministry of Industry and Commerce regulations limit total harmonic voltage distortion on the electric distribution system and limit values of harmonic currents high in customer connection points. Meter power quality analysis of Hioki PW3198 measured value and phase angle of each individual harmonic levels from 0 to 50 and total harmonic distortion voltage / current international standards IEC61000-4-30 Edition 2 Class A.
