Power quality is critical to every industrial environment, especially those involved in industrial water treatment.
Electrical equipment used in water treatment facilities include motors, pumps and variable speed drives (VSDs), which can be vulnerable to interference. If left unattended, these power issues can impact productivity, causing unplanned outages and lasting damage to electrical equipment on site.
The need for protection is clear. According to pump supplier Deckpro, pumping stations account for nearly 20 per cent of the world’s electrical energy demand, with a 7.5 kW pump consuming 65,700 kWh per annum when running constantly at full speed. Therefore, for most sites, downtime is not an option.
In many pump systems and wastewater treatment plants, power quality issues are commonly caused by non-linear loads, often VSDs. While designed to control the torque of motors driving critical equipment, VSDs can also disrupt operations. For example, they can introduce harmonics — causing electrical treatment technology to overheat or fail.
The challenges of water treatment facility power
Voltage and supply issues in wastewater treatment plants include harmonics and voltage sags and swells. If left unattended, these can have far-reaching effects across the treatment plant, causing both short-term inconveniences and long-term damage.
Symptoms of power issues include:
- Unexplained equipment downtime
- Premature component failure
- Unexpected power events and issues with the control panel
- False zero crossings of the sine wave
- Communication errors and ghost errors
Other common problems include incorrect operation of borehole depth sensors, rotary valves, fire alarms and residual current devices. Also, ACB false ground faults and interference with analogue signals are possibilities.
Finding the source of these problems can be like looking for a needle in a haystack. Plant operators and engineers can spend hours trying to find the root cause — and still not get to the bottom of things.
Tackling supra-harmonics
Pumping stations and water treatment facilities are vulnerable to a specific issue — supra-harmonics. These are current and voltage waveform distortions in the range of 2-150 KHz. They present a unique challenge for power engineers and equipment operators.
Supra-harmonics are graded in two areas of noise: 2-9 KHz and 9-150 KHz — an area most oscilloscopes and other power quality devices can’t read.
Since the Engineering Recommendation G5/5 extended the values for planning and compatibility levels to the 100th order (5 KHz), most measurement and mitigation devices are yet to catch up. Even if a pumping station or treatment plant uses measurement devices, it's unlikely that it can measure beyond the 50th harmonic.
Why measuring power is key to pump station maintenance
Rapid detection and mitigation are vital for protecting electrical equipment: transients can appear, cause lasting damage, and disappear in a few millionths of a second. A typical voltage spike lasts one to 30 microseconds and can reach over 1,000 volts.
Using power quality meters, engineers can strategically sample the AC voltage supplying treatment plants at different points and locations and capture slowly changing variations in the electrical waveform. This means they can identify any issues before they cause lasting damage to alarms, borehole depth sensors and other equipment.
Many low-level power and energy meters will only measure voltage, current and power factor. Engineers can enjoy more advanced troubleshooting by investing in a Class A meter, which measures up to the 100th harmonic and provides the accuracy needed to inform discussions with the distribution network operator (DNO).
When choosing a metering device for your treatment plant, there are two categories to choose from:
- Fixed meters
- Portable meters
The choice of meter will depend on how long you want to monitor the system, and if you need a snapshot or long-term picture. For example, if fire alarms randomly go off, you can use a portable meter to perform spot checks and gain insights at several locations. Meanwhile, strategically installed fixed analysers can facilitate root-cause analysis by mapping long-term trends.
We recommend installing fixed meters at multiple locations and recording data over several weeks, even months, to get a complete picture and support regular maintenance.
Once we arrive at your facility, our team of engineers can provide hands-on support with our M.A.R.S. service.
M.A.R.S. stands for:
- Measure
- Analyse
- Report
- Solve
This means our engineers will capture, review, and analyse any power quality data from your plant and feed it back to you in a detailed, actionable report. From this, we can recommend and supply an appropriate solution.
Keeping your wastewater treatment system online
We can help you resolve a wide range of power quality issues before they spread and cause lasting damage.
For pump systems, our power mitigation devices include:
- SineTamer® transient voltage surge protection (TVSS) devices
- Active, passive and hybrid harmonic filters
- Uninterruptible power supply (UPS) devices
- Power factor correction and static var generator (PFC/SVG) equipment
- Dynamic voltage restorers (DVR)
If you have any questions about these products, ask our power quality support team — they can provide the answers you need!
Give your pump station maintenance a boost with better power quality
If you’re concerned about harmonics, supra-harmonics or any other issues, work with an experienced power quality partner who can help protect your treatment plant in a cost-effective way. Contact us to find out how we can support you.
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