Infrastructure equipment such as data concentrators and broadband backhaul routers represent a large portion of the cost of electric utilities’ advanced metering infrastructure (AMI) networks. Reducing the required capex by optimizing infrastructure deployments helps improve overall project’s return on investment.
Utilities deploying…
Protection relays are used to protect high- or mid- or low-voltage power systems, sense an abnormal condition in the circuit, and command the operation of circuit breakers. Voltage and current inputs from the equipment being protected are connected to the protection relay.
Protecting power-system elements requires accurate measurement of three-phase voltages and…
Continued from Part 1 of my blog series on quantifying harmonic distortion.
As a less computationally intensive alternative to calculating each harmonic RMS value for THD, you can estimate THD by calculating the total RMS of the harmonics (excluding the fundamental). First, calculate the RMS of the fundamental and subtract it from the total RMS. Equations 1 through…
Solar inverter: Before and after GaN
“PG&E has called a SmartDay event for Thursday, 07/28/2016 for your residence. Remember to reduce your energy use between 2 p.m. and 7 p.m. to save energy when electric rates are highest.”
Having lived in both Texas and California, I'm used to hot and sunny summer days. I’m also used to receiving the text messages from our local utility like the one above. I need to…
Although electric vehicles (EVs) are not new to the marketplace (they’ve actually existed for over a century), their adoption has been particularly slow. Advancements in battery technology, along with policy regulations that support alternative energy sources for transportation, have accelerated adoption. But EVs still face stiff competition from a broad network of gas stations…
The proliferation of nonlinear electric loads is threatening electric grid reliability in industrial, commercial and residential premises. What are nonlinear loads? They are any piece of electric equipment whose impedance changes with applied voltage. Examples in industrial applications include large variable-frequency motor drives or high-current arc welders.…
In circuit-breaker applications, successive approximation register analog-to-digital converters (SAR ADCs), internal to the microcontroller (MCU) or external, are preferable to delta-sigma ADCs due to their faster startup times. Yet delta-sigma ADCs provide higher dynamic range and higher resolution, an internal PGA (programmable gain amplifier) and…
Heat-cost allocators (HCAs) are intelligent electronic devices which are used to measure the amount of heat energy used by individual units in multi-dwelling buildings which use a centralized, radiated heating system. This measurement is used to allocate the overall cost of operating the central heating system.
HCAs are probably…
I don’t know why I bother checking the weather this time of year. Save for the occasional thunderstorm, I can pretty much guarantee that it’s going to be hot and sunny here in Dallas all summer long. As we enter a long stretch of triple-digit highs, most people’s minds are on how to stay cool. For me though, every time…
Can you imagine a cab without fare meters? Without a fare meter, the cost to drive around the block or travel between two cities would cost the same. Similarly, it is difficult to charge for water services fairly without a water meter. Thus, meters of all kinds have become integral parts of our economy and…
The power consumption of a server station or data center is easily in the megawatts – a data center with 50,000 servers likely consumes 15-20MW. What are the key technologies to manage the power supply for each server rack (Figure 1)? Similarly, there are large electricity consumption companies in industrial and manufacturing, how does the facility manager evaluate…
While the deployment of photovoltaic (PV) systems has grown exponentially over the past 10 years, solar energy still powers only a small percentage of the grid. What has kept solar power systems, a clean form of energy, from powering a larger percentage of the grid worldwide? Concerns over cost ($ per…
In part 1 of this blog series, I reviewed the wireless M (wM)-Bus protocol standard in the 868 MHz ISM band in Europe, while in part 2 I looked at wM-Bus N-modes and the European Telecommunications Standard Institute (ETSI) category 1 receiver performance. In part 3, I listed the pros and cons of a two-chip MSP430™ microcontroller (MCU) + CC1120 RF transceiver combo versus the latest single-chip wM-Bus subsystem…
In the last installment of this series, I explored different standards around the connection of alternating current (AC) voltage to an electric vehicle. In all of those cases, the electric vehicle (EV) has an onboard AC-to-DC (direct current) converter to handle much of the complex portion of the power-delivery equation. However, due to space constraints and the increased difficulty of designing automotive-grade electronics…
What is power quality?
Power quality can have different meanings depending on whether one is an energy producer or consumer. For utilities or system operators, power quality can indicate the reliability of the grid to deliver electricity without interruption. Power quality can also refer to the delivery of power compatible with the electrical loads used by utility customers or the resiliency of the grid to quickly…
As electricity travels from generation stations to utility customers, end-equipment in the smart energy grid ensures the successful delivery of electricity to consumers and accurate monitoring of consumer consumption for billing. Energy-grid equipment must be resistant to electrical disturbances such as electrical overstress (EOS) from lightning strikes, disturbances or transients…
Wouldn’t it be nice if you didn’t have to pay anything for your daily energy use (electricity, that is)? The energy grid is a complex system that generates energy, transmits it over many miles, and finally distributes it to homes and offices. The grid will do its job as long as a means for generation exists, from coal, other fossil fuels or nuclear power.
With the current generation model, the cost of energy…
Figure 1: Backup power lasts for 6.5 seconds
Everyone wants reliable smart meters. Utility customers want them so that the utility knows exactly when there is a power outage without the customer having to tell them. Early notification allows the utility to move quickly to restore power. The utility wants them so that they don’t miss even a portion of customer usage. After all, they can’t charge you for consumption…
With electricity providers striving to reduce energy loss, energy theft prevention is a major concern. Specifically, utility companies seek to prevent energy meter tampering that may lead to obtaining electricity that is not properly billed by the meter to the customer. To prevent energy theft due to the unauthorized modification of energy meters, many markets require that meters include anti-tamper mechanisms to not…
Projections from a research firm[1] indicated that 2015 would likely be a record year with 25 percent growth for solar installations; and the amount of energy capacity generated from solar would grow to 50 GW worldwide compared to 40 GW in 2014. One of the key end equipments in each of these solar energy harvesters is a solar inverter. A solar inverter, or any kind of inverter for that matter, will take a direct current…
As more equipment and appliances are equipped with embedded electricity energy monitors to measure and report the devices’ own consumption, I am getting more requests to estimate the real estate occupied by the metering circuit.
When server power supply is the biggest user of embedded energy monitors, the ‘allocated’ metering area is about a square inch with the voltage…
From solar, hydro and wind, to geo-thermal and bio-mass energy, renewable energy accounts for close to 19 percent of the total energy consumed across the world.
Figure 1: Illustration of substation and distribution automation
So, why is renewable energy generation gathering momentum? In Jayanth Rangaraju’s recent article in ECN Magazine, you will discover that advancements in technology and the growing demand…
With the many advantages of using shunts as current sensors, they are often the current sensor of choice for metrology systems.
But as we saw in the previous entry in this series, the lack of isolation provided by a shunt inhibits its use in polyphase measurement. In three-phase star systems, based on Kirchhoff's Circuit Laws, the neutral current is the sum of all…
Now that we have talked about the advantages of using a shunt, let’s discuss the disadvantages of a shunt and how to overcome them.
One particular disadvantage of using shunts is the resulting power dissipation in the current front-end circuitry. Some standards limit the allowed maximum power dissipation in the current front-end circuitry. As a result, the maximum allowed…
Basic Operation
As investment in smarter grids continue around the world, traditional electromechanical energy meters have become inadequate for maximizing the benefits received from grid modernization. As a result, these older electromechanical meters are being replaced by electronic smart meters. These new electronic meters operate by using an analog to digital converter to sense the mains voltage and current drawn…
