WHAT IS A POWER QUALITY ANALYZER?

The utilization of highly energy-dependent equipment has become a traditional thing in any commercial or industrial setting. Apparently, keeping machinery working at maximum efficiency has been a never-ending concern for technicians and plant managers. This is where power quality comes in, an important element required in maintaining a device’s optimal performance. Unfortunately, it is often overlooked when it comes to routine maintenance and/or troubleshooting.

WHY IS POWER QUALITY CRUCIAL?

Low power quality simply results in higher energy costs, not to mention the toll it takes on any machine or equipment. When energy is poorly used, an excess in power usage subsequently happens. It also leads to utilities requiring more financial penalties due to high peak demands and poor power factor. In simple words, low power quality affects the costs of maintenance and repairs, as equipment tends to fail or get damaged.

THE COSTS OF POOR POWER QUALITY

About 150 billion Euro is the annually cost of low power quality in the European market according to the Leonardo Power Quality Initiative and The Electric Power Research Institute (EPRi) found  losses of 119-188 billion US dollars in the US market. EPRI  found the most interesting finding: 80% of power quality interference are generated within a facility.

The impact of poor power quality is measured in three general areas: downtime, equipment problems and energy costs.

HOW POWER ANALYZER HELPS?

As the name suggests, a power quality evaluator is designed for the sole purpose of identifying issues involving power quality. It works by strategically sampling the AC voltage at various points along a waveform shape. From there, it digitizes all points or values and utilizes a microprocessor in order to execute a numerical analysis (which arrives at harmonic frequency magnitudes).

Being able to monitor current, a power quality analyzer can systematically calculate and display common power values, what gives you a whole picture of how your system works and where it fails miserably. It is worth remembering, however, that PQAs are not all the same. Some of them are built for single-phase systems only, while others are designed to evaluate three-phase systems. So, it is important that you use a PQA that perfectly fits your electrical system, both in design and maintenance.

Here are some important points that will help you find the right power quality evaluator:

●Determine the total power of your system. Is it single-phase or three-phase? Or is there a solar involved?

●Do you require logging and/or connectivity capabilities?

●What sort of values do you want to see on the device’s display?

●What voltage events are you looking to capture (e.g. dips & swells, flickers, harmonics, transients, etc.)?

●Are you interested in other parameters or calculations, such as crest factor, power inverter efficiency, etc.?

●What standards are you looking for a power quality evaluator?

Remember that poor power quality can always result in wasted energy, which means more costs. Try using a power quality evaluator and see the real difference it makes.

Products and reference designs of Power quality analyzer

Power quality analyzers are used to continuously monitor and analyze electricity lines for disturbance which can disrupt the reliable delivery of energy or cause damage to equipment plugged into the grid. Power quality disturbances include events such as voltage sags and swells, transients, harmonic distortion and voltage/current imbalance.

Design requirements

Modern power quality analyzer designs require:

●Current and voltage sensing of poly-phase electricity and revenue-grade energy measurement compliant with ANSI C12.20 and IEC-62053 standards.

●Analysis of power quality metrics such as harmonic distortion.

●Power supply design, digital input/output, real-time networking and wireless communications.

AC/DC power supply

Power quality analyzers are designed for 15W to 30W of power consumption. TI offers several power supply topologies which support wide input AC voltage ranges for various power levels with high efficiency, and isolation if needed. AC/DC power supply includes eFuses & hot swap controllers、Flyback controllers、Shunt voltage references、Series voltage references、Load switches、Isolated DC/DC converters & modules、Transformer drivers, the corresponding products are TPS25921A、UCC28711、TL431、REF3425、TPS27081A、UCC12050、SN6501

Energy storage

PQAs rely on batteries or super caps to provide an energy source during grid outage scenarios for saving data and orderly shutdown of the analyzer. This subsystem can also be used to provide boost current for any wireless connectivity such as WiFi, RF, or BLE. TI provides solutions for super cap energy harvesting and gauge monitoring. Energy storage includes Battery fuel gauges, the corresponding product is BQ27Z558

DC/DC power supply

PQAs have multiple digital, analog, and RF blocks with individual DC power requirements. Depending on the power levels, TI has DC/DC converters, LDOs, Power management ICs (PMIC), and isolated DC/DC supplies that can enhance power efficiency and reduce size. DC/DC power supply includes Multi-channel ICs (PMICs)、Linear & low-dropout (LDO) regulators、Sequencers、Charge pumps (inductorless)、Boost converters (integrated switch)、Buck converters (integrated switch)、Load switches、Ideal diode/ORing controllers、Isolated DC/DC converters & modules, the corresponding products are TPS51200、TLV761、LM3881、REG71055、TPS61046、TPS563211、TPS27081A、LM5050-2、UCC12050

Protection

Protection is designed for any sub systems such as the AFE, wired interface, and AC/DC sub systems that interface to external systems, to increase system robustness. TI offers transient voltage suppressors and ESD protection devices. Protection includes ESD protection diodes、TVS diodes, the corresponding products are TPD4E1U06、TVS1800

Measurement AFE

The measurement AFE subsystem of a power quality analyzer (PQA) samples the current and voltage for each phase of the mains and neutral. Additionally, for accurate measurement, high precision signal chain is required to measure a wide dynamic range of current and voltages in a noisy environment. This subsystem focuses on low speed and high precision amplifiers, references, and data converters. Isolation may be required in this subsystem. Measurement AFE includes Isolated ADCs、Isolated amplifiers、Shunt voltage references、Series voltage references、Isolated DC/DC converters & modules、Clock generators、Precision ADCs、Precision op amps (Vos<1mV)、General-purpose op amps、Signal conditioners、Inductive sensor AFEs, the corresponding products are AMC1305M25、AMC1300、TL431、REF35、UCC12050、CDCE906、ADC101C021、OPA211、OPA323、FDC2212、LDC0851

Transient recording AFE

The transient recording AFE subsystem of a power quality analyzer (PQA) samples the voltage for each phase of the mains, checking for high-speed transient events. This subsystem focuses on very high speed [>1MSPS] signal capture, featuring high-speed amplifiers and data converters. Additional clocking and time synchronization is needed for the high speed signal chain. Transient recording AFE includes Signal conditioners、Inductive sensor AFEs、High-speed ADCs (≥10 MSPS)、Shunt voltage references、Series voltage references、Isolated DC/DC converters & modules、Isolated ADCs、Isolated amplifiers、Clock generators、Clock buffers、High-speed op amps (GBW ≥ 50 MHz)、General-purpose op amps, the corresponding products are FDC2212、LDC0851、ADC3421、TL431、REF35、UCC12050、AMC1305M25、AMC1200、CDCE906、CDCLVC1102、OPA835、OPA323

Isolation

Isolation may be required to isolate the higher voltage line from the user interface side for safety. It may also be required between the system and other connecting devices, which could have different ground potentials. Isolation includes Digital isolators, the corresponding products are ISO7842、ISO6720、ISO6721

Processing

Power quality analyzers use processors with millions of instructions per second to compute power quality factors such as individual harmonic analysis, total harmonic distortion, voltage sag/swell, and other parameters listed in the IEC-61000-4-30 standard. A digital signal processor is used to handle the intensive signal analysis required by high-end PQAs. An applications processor is used to handle the user requirements. Processing includes MSP430 microcontrollers、Supervisor & reset ICs、Low-side switches、Direction-controlled voltage translators、Noninverting buffers & drivers、Monostable multivibrators (one-shots)、OR gates、Comparators、Clock generators, the corresponding products are MSP430G2553、TLV803、ULN2003LV、SN74AXCH8T245、SN74LVC1G17、CD74HC283、SN74LVC2G32、TL331LV、CDCE906

HMI

The human machine interface (HMI) is where the operator will observe data from the power quality analyzer. This subsystem may feature status LEDs and/or displays with touch screen and active dimming. HMI includes Backlight LED drivers、LCD & OLED display power & drivers、Light sensors, the corresponding products are TPS61169、TPS65105、OPT101

Self-diagnostics/monitoring

Self-diagnostics increase the system reliability and extends the operational life of the power quality analyzer. Diagnostics includes monitoring of temperature and humidity, a voltage supervisor for supply monitoring during power-up or a watch dog timer with a voltage supervisor for similar functionality. Self-diagnostics/monitoring includes Digital temperature sensors、Analog temperature sensors、Humidity sensors、Temperature switches、Supervisor & reset ICs, the corresponding products are TMP513、TMP235、HDC3022、TMP303、TLV803

Clocking

External clocking is needed to synchronize the timing of various clocks in different sub systems, including the AFE and processing subsystems. Clocking includes Clock generators、Clock buffers, the corresponding products are CDCE906、CDCLVC1102

Memory

The host processor is interfaced to memory for executing instructions and for data processing and storage. TI offers Active Power Termination (with sinking and sourcing) to reduce power dissipation and to improve data read/write accuracy and integrity, minimizing reflections, distortions, cross-talk, ground bounce and jitter concerns. Memory includes DDR memory power ICs, the corresponding products are TPS7H3302-SP、TPS7H3302-SEP

Wireless interface

Short range networks such as Wi-Fi and BLE are used in industrial installations for user configuration and data transmission. TI has low power wireless connectivity solutions to enable this feature. Wireless interface includes Other wireless products、Low-power 2.4-GHz products、Sub-1 GHz transceivers、Wi-Fi products, the corresponding products are CC2530-RF4CE、CC2651R3、CC1120、CC3200

Wired interface

Power quality analyzers support various serial communication interfaces, including ethernet, RS-485, and RS-232. In some industrial applications it also supports 4-20mA current loops and analog and digital (pulse) I/O to interface with legacy utility systems. Wired interface includes RS-485 & RS-422 transceivers、ESD protection diodes、RS-232 transceivers、I2C & I3C level shifters, buffers & hubs、I2C general-purpose I/Os (GPIOs)、TVS diodes、C2000 real-time microcontrollers, the corresponding products are SN65HVD3082E、TPD4E1U06、TRS3232E、PCA9515A、TCA6408A、TVS1400、TMS320F28377D