Technology Feature Feature Driving a Pump in Harmonics Some of Britain's new legislation has allowed engineers to start controlling the harmonics generated by the frequency converter. Paul Pryor of Schneider Electric Industrial Systems and Solutions outlines the harmonic issues in pump applications and explains the new drive technology that can withstand harmonic problems and mechanical resonance. This may be a direct, convenient and economical way to save energy in all types of pump applications. Figure 1. The frequency converter not only helps to solve the energy efficiency problem, but also refers to improving the disadvantage of the pump, such as pump weight and unbalance. Figure 2. Special problems in the pumping plant for sewage treatment plants (such as harmonics) can be eliminated by simple corrective measures. Figure 3. The water pumping station not only benefits from inverter control but can also be automated. Harmonicity in pump inverter control is a long-standing problem, but the recently introduced British Institute of Electrical Engineers Engineering Guideline G5 / 4-1 underscores this issue. In fact, under the G5 / 4-1 standard, regional power companies can refuse the possibility of harmonic distortion of the equipment connected to the grid. However, in addition to the legislative factors of electronically controlled pumps, there are also mechanical resonance problems that can lead to excessive noise, heat and premature component failure. Harmonic Elimination A common method of resolving harmonic problems is to configure a 12-pulse AC rectifier. However, few data show the effectiveness of this device in mitigating harmonics to meet the G5 / 4-1 standard. According to an article published by Karl Hink, a MTE company in the United States, 12-pulse rectifiers do not meet the harmonic mitigation levels most engineers expect. These rectifiers do not meet IEEE-519 requirements in real world conditions. However, the purpose of this paper is to describe the general application of the pump, focusing on new drive technologies that overcome harmonic and mechanical resonance problems. As we all know, inverter control makes VSD help to save energy. As a result, when the UK started to levy a Climate Change Levy, it set out the cost of compensating pumps for installation. So we will not just focus on the province's energy saving potential of this converter. Mechanical imbalances can cause resonance in the equipment, for example using a frequency converter may stall the pump's blades. By comparing the speed at which simple recording pumps produce resonance, these frequencies can be "skipped" with a simple function of the frequency converter. However, there are some new technologies that can overcome the proliferation of electronic harmonics. Frequency converter manufacturers have specific harmonic problems into their equipment's anti-harmonic solutions. Schneider Electric, in developing its newest series of non-harmonic frequency inverters, suggested that the main culprit in generating harmonics is direct current. By reducing the DC capacitance, a standard 6-pulse frequency converter can greatly reduce the harmonics, thus improving the efficiency of the inverter. Next Generation Drives The Telemecanique brand under the Schneider Electric Group introduces the new Altivar 21 series drive with its full range of pump functions and innovative design to minimize harmonic dispersion and save energy directly for all types of pump applications A convenient and economical way. Altivar 21 drives replace constant-speed starters, enabling users to save energy and avoid the inconvenience of mechanical flow and pressure control devices, such as valves, throttles and diverters, which are often not reliable. In addition, in most applications, the cost and installation of a new drive will be 100% tax-free in the first year, in line with the UK government's Enhanced Capital Allowance program. The Altivar 21 is a three-phase inverter with a power range of 0.75-75 kW and can be installed as an IP20 device in a control board or as an IP54 device without the need for additional protective caps. All types of low-value DC capacitors, compared to general purpose industrial frequency converters, minimize the occurrence of harmonics. Electromagnetic compatibility (EMC) performance is optimized with an integrated filter that simplifies inverter installation, saving space by eliminating the need for an external filter. The Altivar 21 drive's standard features include a PID regulator for effective control of flow and pressure, automatic spin-load pickup and adjustment of switching frequency, noise and resonance cancellation, and current limit based on motor speed. Power Factor Most engineers believe that the Altivar 21 can typically produce a uniform power factor, while high-speed switching configured in an AC rectifier results in a reduction in power factor. In all AC variable frequency pumps, the power factor must be affected. However, few users are aware of the increased power consumption caused by a reduction in power factor, which affects the cost of electricity. Schneider Electric can not change the physical principle, but to mention a simple and economical method of power factor correction. The perfect theoretical power factor of 100% or unity, how to use all the power from the power grid for functional applications. However, many devices require electrical power prior to normal operation, for example, the motor must be energized to generate magnetic flux before the motor is running. This energy is called reactive energy, and at the same time it is invisible, but appears as a power bill. Power factor correction devices use capacitors to provide reactive energy so that all energy from the power grid is used for functional applications. The power correction device is mainly composed of a capacitor, which stores the energy of the starting coil (for example in a motor). The use of reactive energy is minimized. Schneider Electric's Merlin Gerin Power Factor Correction Board features a modular structure that enables installation of the application at the lowest cost required for configuration. The company can also help users calculate power factor through engineering and service teams and investigate power quality issues. Schneider Electric's website (www.schneider.co.uk) also has an online power factor correction calculator to check power factor levels. The power factor calculator takes just three values, which can be found on any power bill, to figure out how much power can be saved and how many kilograms of carbon dioxide emissions can be reduced each year, and how much power can be used for other loads. Directly from the emai page, Schneider Electric representatives analyze these results based on many years of energy-saving experience, recommend on-site surveys (if appropriate), and then provide the most efficient way to save energy.