Pulse 74 Ali Sebt

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INTERVIEW


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Ali SebtPRESIDENT AND CEO OF RENESAS ELECTRONICS AMERICA

Keynote Address from Renesas DevCon 2012

Why Distribution Automation (DA) is considered to build upon in developing the Smart Grid as

it transforms the distribution network towards more automation.

RTZ - Return to Zero Comic

Featured Products

BY NICHOLAS ABI-SAMRA WITH QUANTA TECHNOLOGY

4

13

14

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Distribution Systems Automation and

Review of the Rigol DSA-815 Spectrum

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BY CHRIS ANDERSON WITH ECE101A detailed look into the specs and features of a new spectrum analyzer from Rigol.

Analyzer

Optimization - Part 1


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4 EEWeb | Electrical Engineering Community


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Good morning, my name is Ali Sebt, President and CEO

of Renesas in the Americas. When we were putting this

video together, the thought that came to mind was that

the sensationalism that exists in the news todaywars,

famine, austerity measuresand all of the challenges

that we as adults face, are very stressful. And oftentimes,

I found myself very worried for my childrens futureI

have a 14-year-old son and a 12-year old daughterandI found myself very worried for their future. However, I

realized that when I talked to my children, they had a

very different perspective about their future. They see a

future filled with possibilities. Sometimes, they say they

want to be a doctor or a football player or a ballerina and

Im sure all of you who have children have experienced

this; from time to time, they change what they want to be

in the future. That says that they see a world and a future

full of possibilities.

* * *

While Renesas is here today to share with you the

techniques and the latest products we have to offer

for embedded applications. The underlying unity and

connection we have is joint responsibility we have for

our children and the next generation. If we go back

to the early 1800s, the worlds population stood at 1

billion. Fast forward a hundred years and the worlds

population doubled to 2 billion. Fast forward to today,

and the worlds population stands at 7 billion. We also

know at the same time, throughout the past 100 yearsor so, that extracting fossil fuels has also become a

challengeour resources are becoming more scarce.

At the same time, theres a third dimension, which is

the fact that all of us are utilizing more electricity and

more power because all of us have more gadgets and

electronics surrounding our lives. So, the purpose of

this presentation is to talk about how we, as solution

providers, and you, as embedded designers, can find

a solution to these diametrically opposed forces; more

people, more inhabitants, more users, less energy and

more energy requirements per individuals.

This Smart Societyor the challenges that face the

Smart Societycan be addressed by four areas: low-

power electronics using low-leakage semiconductors;

taking advantage of the proliferation of sensors

sensors are becoming ubiquitous around us; taking

advantage of the signal chainwhat Renesas provides

(analog, microcontrollers and power stage)and

finally; security.

Lets begin with low-power semiconductors. If we go

back to the mainframe era, the focus of computing was

really executing faster transactions. As we fast forward

to the PC era, the focus was faster graphics and faster

execution of instructions with limited focus to powerconsumption. Of course, in the last decade, as the

networking and Internet grew around us, the focus was

how we push more video and packets down the pipe.

Throughout these decades, there has been little regard

to how we address power consumptionits all been

about performance. Renesas, on the other hand, for the

past three or four decades, has been focusing on low-

leakage transistor technology. Our microcontrollers are


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SPECIAL FEATURE


developed with the very intent focus of developing low-

power consuming technologies.

Over the past few decades, in general, embedded

systems have focused on performance, and nowtheres an imbalance between performance and power

consumption. At the onset of this decade, we have seen a

shift in this balancewe now have commercial-electric

vehicles on the road, we have computer devices that

truly do consume low-power. We have seen a shift in the

mentality of embedded designers toward focusing on

low-power consumption appliances. I will touch on one

of our microcontrollersthe RL78which addresses

the 8- and 16-bit space. We mention true low-power

because I know you as engineers are always skeptical

with specmanship. We know that some suppliers fine-

tune their MCU architecture so that it works well in

one mode and not necessarily in other modes. Oftentimes, you have a challenge duplicating the results in

your end system. Renesas provides a true low-power

microcontroller in this area and Ill show you some of

the numbers.

In Run mode, the RL78 consumes 144 micro-amps

per MHz. The closest competitor is Company S at 150.

Remember, I said earlier that competitors fine-tune their

The underlyingunity and

connection we

have is joint

responsibility

we have for

our children

and the next

generation.


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microcontrollers to be low-power in one mode. Now as

we go to the next mode, which is the Halt mode, youll

see that the RL78 consumes less than half of one micro-

amp. But the previous competitor, which was Company

S that was the closest, is now off the charts.

Lets go to the Stop mode. In this mode, and in Smart

Society applications, this is one of the mode that yourMCUs will most likely be in. You see that the RL78 is

really showing off its low-leakage transistor capability.

Now in this case, youll see that Company T, which was

closest to us in the Halt mode, is now off the charts.

We have also added a very special mode, called the

Snooze mode, which is unique to Renesas. The

Snooze mode allows, for example, the ADC to wake

up and do some measurement and, if necessary, turn on

the microcontroller to go into the operation Run mode.

You can see how much power savings youll have if you

are running system at 8 or 32 MHz. Incredible savingsusing the Snooze mode.

Let me now talk about sensors. As I mentioned, sensors

are around us and are becoming ubiquitous. In order

for the Smart Society to be effective, we have to take

advantage of our analog, real-world environment. Lets

take, for example, irrigation. Often times, we drive

by parks, golf courses, and lawns where we see that

the driveway is wet because water seeps throughthe soil at different rates. Soil is made up of different

compositions; theres clay, sand and three other types.

This is why you see dry spots and wet spots. Imagine if

we embed moisture sensors in the ground that will be

able to communicate back to the control panel if an area

of the lawn has had enough water. We know that water is

also very precious, so we not only want to conserve the

energy that delivers water, but water itself. Of course, as

embedded applications are connected to the Internet,

you will know if there is rain in the forecast that day

and will prevent the irrigation from watering that lawn

altogether.

CPU

RUN

Clock

Peripheral Device

CPU

STOP

Clock

Peripheral Device

CPU213

Micro-Am

ps/MHz

400

350

300

250

200

150

100

50

M S T A RL78

Condition

Match

No Condition

Match

SNOOZE

Clock

Peripheral Device

CPU

HALT

Clock

Standby

Running

Peripheral Device

150

363

380

144

CPU

RUN

Clock

Peripheral Device

CPU

STOP

Clock

Peripheral Device

CPU

HALT

Clock

Standby

Running

Peripheral Device


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At the onset of this decade, we haveseen a shift in this balancewe have

now commercial-electric vehicles on

the road, we have computer devices

that truly do consume low-power.

5.1Micro-A

mps

14

12

10

8

6

4

2

M S T A RL78

3.4

10.3

14.3

0.23

CPU

RUN

Clock

Peripheral Device

CPU

STOP

Clock

Peripheral Device

CPU 5.6

Micro-A

mps

12

10

8

6

4

2

M S T A RL78

Condition

Match

No Condition

Match

SNOOZE

Clock

Peripheral Device

CPU

HALT

Clock

Standby

Running

Peripheral Device

12.5

3.6

10.6

0.49


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Lets take this sensor concept to the next stage. We

know that in the automotive arena, more and more

companies are deploying frontal-view cameras for

safety. We also know that they are deploying frontal view

radar for safety. However, none of these sensors alone, is

adequate to provide enough intelligence for the onboard

computer to make a smart decision for safety purposes.

So the next stage in utilizing sensors is sensor-fusion,

where you need to have enough performance with your

microcontroller to take in these different types of sensor

data, fuse them and make an intelligent decision.

Lets look at conference rooms and building

environments. We see the deployment of temperature

sensors, humidity sensors and passive infra-red

sensors. Detectors, using our analog microcontroller

and power semiconductors, are being deployed in

local areas to take advantage of this raw-data, fuse

that data, and make an intelligent decisions based on

that environment. Heres an example: these detectorsthat take localized sensor information and provide

intelligent information back to the central unit can aide

an emergency response team so they will not have to go

to every floor and area in a burning building so that they

can focus on saving lives.

Youve seen sensors, sensor fusion and detectors, so

lets talk about how the detectors are builtwhich is

where the signal chain comes in. All of these sensors

provide analog information. This analog information

first has to be conditioned and amplified so that the

microcontroller can receive it in the right format. Then,the microcontroller will fuse this information and make

an intelligent decision. But remember, you are no longer

in an on/off worldyou are in a world of multiple analog

and multiple forms of information, so you need a highly

powerful and low-power consuming microcontroller

that can mathematically and algorithmically compute

this information and make the right decision. And, of

course, coming out of the microcontroller is the power

stage, which will invoke a decision back into the real

world.

Renesas has introduced a new technology called Smart

Analog. Its a singular device that has a programmable

and re-configurable analog front-end, which is basically

made up of op-amps mated with the true low-power

RL78 MCU into one package. So, using a web-based,

GUI IDE, you can design, test and validate your system

in one day without having to build a physical system and

tune the analog system all day long. Of course, your

component count will be reduced almost 10 to 1. When

you think about it, you no longer need to have your


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resistors, diodes and capacitors on the board, because

its all going to be programmable and re-configurable

in this one chip.

Lets talk about security. With the Internet of things,

which is a part of this Smart Society, machines are going

to be connected to everything in the network. With a

machine-to-machine connection, its very important to

secure your information and secure the credentials ofwho will have access to your machines. When we talk

about security, we are really talking about authentication.

Typically, in machine applications, there are three

levels of authentication. First, you have to authenticate

the user. Second, you have to authenticate the machine.

And third, you have to authenticate the services. So,

in this example, if a friend comes to your house and

wants to charge their electric vehicle at your house, you

obviously dont want to pay for that. The utility company

will authenticate your friend, in this case, so they know

who to bill. They will authenticate the electrical vehicleso they know what kind of charging is required for

this vehicle. And, of course, they will authenticate the

services so they know how to bill, where to bill and so

on.

Our DNA and our R&D, as we develop these products

and solutions for our smart society, are focused on these

fundamental areas: how do we enable you to generate,

store, control and ultimately save energy. All of our

products and solutions are designed and developed

with these areas in mind.

To watch the entire keynote address

and other Renesas videos on their

YouTube page:

Click Here
http://www.youtube.com/playlist?list=PL8B1DC420CF309108&feature=plcphttp://www.renesas.com/http://www.youtube.com/playlist?list=PL8B1DC420CF309108&feature=plcp


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Present day Distribution Automation (DA) goes beyond reducing manual

procedures. DA makes distribution systems more controllable and flexible based

on accurate data for decision-making applications. This is accomplished through a

set of intelligent sensors, processors and fast communications to remotely monitor

and coordinate distribution assets.

DA is considered a foundation to build upon in developing the Smart Grid as it

transforms the distribution network towards more automation.

Nicholas Abi-SamraVice President of Quanta Technologies

Distributi

Systems

Part 1

Automation &

OptimizationVice President, Asset Management - Quanta Technology


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n


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Distribution Automation History and Initial

Concepts

Over 30-40% of the total investments in the

electrical sector go to distribution systems,

yet, they have not received the technological

impact in the same manner as the generation

and transmission systems. Up until recently,

most of the distribution networks haveworked with minimum monitoring systems,

mainly with local and manual control of

capacitors, sectionalizing switches and

voltage regulators and, without adequate

computation support for the systems

operators. This is now changing, with the

trend increasingly moving to automate

distribution systems to improve their

reliability, efficiency and service quality.

Over the years, Distribution Automation

took many shapes, form local automation

with no communication requirements, to

more advanced, two-way communication,

as shown in Table 1. The concept of

automation in distribution systems has been

around for many decades, but had a ripple

in in the 1970s, albeit at a sporadic pace,

for the improvement of distribution system

operating performance. Early automation

applications included capacitor switching,

voltage regulation and limited feeder

reconfiguration. From the 1990s distributionnetworks started to come under pressure

to improve the quality and reliability of the

delivered power. Efforts to make the power

distribution systems smarter started to get

hold and traditional distribution automation

(DA) was born.

During those years, the use of reclosers and automatic

switches to reduce outage times became more

widespread. In addition, due to deregulation, distribution

systems also came under cost pressure for optimization

of operation and maintenance practices. In the 2000s,

the above pressures increased along with new ones

such as the ever increasing occurrences of distributed

generation in many forms in MV and LV networks.

These requirements are pushing further the need

for monitoring, automation, control and protection of

distribution systems. DA applications have been related

with the deployment of SCADA (Supervisory Control

and Data Acquisition) technology in the distribution

circuits and substations.

TypeCommunicationsRequirements

LocalAutomationNo

Communications

Monitoring& ControlOne-WayCommunications(Limited Bandwidth)

AdvancedDistribution

AutomationAdvanced Two-WayCommunications

Example Applications/Automation Level

Sectionalizers: Automated faultrestoration via pre-programmedsequencing.

Voltage regulators: Automatedvoltage regulation for long feeders

Remote control of capacitors andfeeder reclosers

Messages from short circuitindicators control center for fastfault location

Distribution line monitoring

Power Quality (Harmonic content)measurements

Fault detection and restoration

Automatic reconfiguration offeeders

Voltage regulation and reactivepower control for:

Reduction of line voltageduring peak load conditions,or for energy conservation

Reduction of system losses Buck/boost bus voltages in

case of abnormal situations,such as threat of voltagecollapse, back-feeding, etc.

Distribution underground networkgrid monitoring and control

Supporting Distributed EnergyResources (DER) and microgrids

Complementing AMI

Interacting with transmission system

Distribution Automation (DA) or Advanced

Distribution Automation (ADA)?

Some like to divide the terminology used for DA and

ADA, in the sense that the former is concerned withautomated control of basic distribution circuit switching

functions, while the latter, ADA, is concerned with

complete automation of all the controllable equipment

and functions in the distribution system. In this

document, the term DA is chosen to automation applied

to the distribution system, with regard to the above

distinction.

The number of DA projects at the different utilities is


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TECH ARTICLE


increasing, with different approaches. Many of these

projects encompass a large area of a distribution

system. It is unlikely that any one approach of DA will be

the sole preferred technique for utilities. There are too

many differences between various utilities -- and even

within an individual utility -- to justify a universal solution.

Benefits of Distribution Automation

The benefits of DA can be grouped into three bins:

operational, customer-related and financial:

Distribution Circuit Congestion

Most distribution systems in the United States were

designed decades ago based on the loading analysis

performed at the time. These were based on historical

load profiles, statistical analysis with some assumed

diversity factors.

Many distribution circuits have been operating closeto their operating limits, and additional load may push

them above their emergency operating limits. Several

electric vehicles (EV) plugged into the same circuit

could cause a localized overload on the distribution

circuit and transformers while these are subjected to

variations in demand due to normal customer activities.

The unbalanced conditions created by such loads are

on top of imbalance due to the large number of unequal

single-phase and double-phase loads. The above

could result in degradation of customer power quality,

congestion on certain feeders, voltage concerns on

longer feeders and increased line losses.

The major changes in load types, levels and load

patterns may now require upgrades to the transformers

and other equipment or shifting loads between

transformers.

II. FEEDER AUTOMATION

Feeder automation is an important part of distribution

automation and has received considerable attention

over the last few years. Many approaches have been

proposed and implemented in power utilities worldwide.Progress in large scale distribution automation has

been slow due to the massive investments needed,

but funding by the federal government for utilities

implementing smart grids has accelerated deployment

of these technologies.

Feeder automation is implemented either based

on a centralized approach or a distributed one. A

centralized approach is capable of providing complete

FA functions but requires large scale implementation.

A distributed approach is simpler, more flexible, can

be implemented in a small scale but can only provide

limited FA functionalities.

III. FEEDER RECONFIGURATION

Distribution systems are normally configured radially

for effective coordination of their protective devices.

Two types of switches are generally found in the system

for both protection and configuration management:

1. Sectionalizing switches (normally closed switches)

OperationalBenefits

CustomerBenefits

FinancialBenefits

Better fault detection, isolation andrestoration

Reduced outage duratiion

Improved voltage profile and reactivepower (VAR) management/optimization

Better visibility into the grid and moreaccurate data informaation for systemoperation and planning

Better component loading

Better quality of supply and servicereliability

More customer choice

Less manual labor

Decreased interruption costs2

Improved utilization of system capacity

Better customer retention for improvedquality of supply

I. THEN AND NOW: THE DISTRIBUTION POWER

SYSTEM, TWO DIFFERENT ENVIRONMENTS

The increasing penetration of residential and municipal

solar generation, and the distributed generation in

general, impose challenges on the existing distribution

infrastructure and the system operator. New flow

patterns may require changes to the protection and

control strategies, enhanced distribution automation and

microgrid capabilities, capabilities, voltage and VAR

management, and over all enforcement of distributiongrid infrastructure. The changes are best depicted in

the Figures 1 and 2.

2 Over the next 10 years, individual utilities may use variouscombinations of DA approaches across their service areas to create

reliability tiers to maximize customer and utility value. The creation

of reliability tiers could introduce new utility revenue models and

would allow commercial and industrial customers to choose

between higher-grade utility power or expanded uses of back-up

generators, to lower consumers overall energy costs.


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2. Tie switches/breakers (normally opened

switches).

By changing the status of the sectionalizing and

tie switches, the configuration of distribution

system is varied and loads are transferred among

the feeders while the radial configuration format

of electrical supply is preserved and all load

points are not interrupted. Feeder reconfigurationentails the modification of the topology of an

electrical system by closing or opening tie and

sectionalizing switches, in order to obtain a better

performance of the system. It has been used

to improve voltage regulation balance, feeder

loading, as well as reducing system losses.

Examples of objectives of feeder reconfiguration

include: real power loss reduction, equipment

(e.g., transformer and feeder) load balancing,

phase balancing, system restoration, bus voltage

profile improvement, increasing reliability andpower quality improvement.

Real Power Loss Reduction

Under normal operating conditions, the network

is reconfigured to reduce the systems losses.

One method which can be used to achieve this

is through an explicit formula for determining

the variations in system losses, three-phase

line flows and voltages in terms of system and

network data, with respect to variations in control

devices, network components and connections.Transformer losses can be minimized if the

substation transformers are loaded in proportion

to their capacity.

The reconfiguration of the system for reliability

and loss reduction can be accomplished in an

automated mode using the same sectionalizers

which are used for fault isolation and service

restoration.

From a practical point of view, reconfigurationonce every few hours would be sufficient for loss

reduction. The additional benefit of more frequent

reconfiguration is very minimal.

Equipment Feeder Load Balancing

Feeder reconfiguration may be used to avoid over

loading of critical transformers (and/or feeders)

resulting from load variations. In order to keep

the system reliable, a part of the load from the

Figure 1: Then...Simplified Power Systems

Figure 2: Now...Excepted Changes in Flows ofElectric Power

Generating Plant

Transmission System

Circuit Breakers

Feeders

Sectionalizingswitch

Lateral feeder

Home

Capacitor bank

VoltageRegulator

Sub-transmission System

Distribution System

Unidirectional

PowerFlow

Generating Plant

Transmission System

Circuit Breakers

Feeders

Sectionalizingswitch

Lateral feeder

Home

Capacitor bank

VoltageRegulator


Distribution System

Unidirectional

PowerFlow

Power Flow

Generating Plant

Transmission System

Circuit Breakers

Feeders

DG

Sectionalizing

switch

Lateral feeder

Home

Capacitor bank

VoltageRegulator


Distribution System

Power Flow


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TECH ARTICLE


overloaded feeder must be transferred to an adjacent

transformer feeder that is relatively lightly loaded.

Similarly main transformer overloading problem can be

addressed by identifying the appropriate feeder causing

the overload and transferring a part of load from that

feeder load to an adjacent transformer which is lightly

loaded. This redistribution of load among feeders and

transformers makes the system more balanced and the

risk of overloading is reduced thereby increasing the

reliability of a system.

The network can be reconfigured to balance load

in feeders and/or to avoid the overloading of critical

transformers and feeders resulting from load variations.

This redistribution of load among feeders and

transformers makes the system more balanced and

the risk of overloading is reduced thereby increasing

the reliability of a system. One method this could be

accomplished is through monitoring certain electrical

parameters (current, voltage etc.) in the system andinitiating breaker trips based on hitting threshold values.

Reconfiguration in Case of a Fault

By the use of remote interconnect switching; utilities

can restore power to as many consumers as possible

during the time of multiple faults. Under conditions

of permanent failure, the network is reconfigured to

restore the service, minimizing the zones without power.

Reconfiguration for Reliability

Predictive reliability models and schemes can be used

to compute reliability indices for the distribution system

in order to apply algorithms to reconfigure the system to

achieve optimum reliability. Thus feeder reconfiguration

presents electric utilities with an opportunity to boost

reliability without the addition of new components.

Equipment Loading and Voltage Drop Criteria

System reconfigurations should not violate equipment

loading and voltage drop criteria; hence, a power flow

for each system configuration needs to be performed toidentify voltage and capacity violations.

Optimization Techniques

Heuristic techniques have been proposed to reach a

near optimal solution for feeder reconfiguration in a

short period. Other approaches have been in which

the optimal configuration was achieved by opening the

branches with lowest current in the optimal load flow

solutions for the configuration with all switches closed.

Fuzzy logic and the combinatorial optimization-based

methods have also been used.

Special Considerations

Reconfiguration with Weighted Objectives

Reconfiguration of the system may be defined in

terms of maximum reliability or minimum losses, ora combination of these two. The task of finding the

optimal balance between them is approached as a

multicriteria/multiobjective optimization problem. On

one hand, we have the customers reliability demands

for power delivery and on the other hand we have the

losses and their economic impact on the system. In

the optimization total customer interruption cost is

used as the measure of system reliability performance

from the customer perspective. The losses costs are

closely related to the analyzed network, its components,

structure and available resources.

It is possible to extend the multiobjective approach

by studying every feeder as an individual objective

instead of the total system. Furthermore, with more

objectives, the solution space quickly becomes difficult

to grasp with the increasing number of load points. It is

interesting to note that the two objectives do not entirely

point the solution in two different directions.

Reconfiguration with Unbalanced Conditions

The actual distribution feeders are primarily

unbalanced in nature due to various reasons, forexample, unbalanced consumer loads, presence of

single, double, and three-phase line sections, and

existence of asymmetrical line sections. The inclusion

of system unbalances increases the dimension of

the feeder configuration problem because all three

phases have to be considered instead of a single phase

balanced representation. Consequently, the analysis of

distribution systems necessarily required a power flow

algorithm with complete three-phase model. Potential

unbalanced conditions created by such loads could

cause problems on main feeders and other laterals.

Feeder Reconfiguration with Distributed Generation

Recent development in DG technologies such as wind,

solar, fuel cells, hydrogen, and biomass has drawn

attention for utilities to accommodate DG units in their

systems. The introduction of DG units brings a number

of technical issues to the system since the distribution

network with DG units is no longer passive.


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EEWeb PULSE


IV. VOLTAGE AND REACTIVE POWER (VAR)

CONTROL AND OPTIMIZATION

As energy demands increase, and power-hungry new

technologies such as electric vehicles proliferate,

utilities will need to find ways to meet peak-load

requirements. Volt-VAR optimization, which reduces

losses from transmission and distribution, can free up

much needed capacity to help meet future demand. Forthat, the industry has progressed from fixed capacitor

banks to one way controlled devices, and now capacitor

banks managed by two-way communications and fully

intelligent controls that operate based on existing

conditions and handle reactive-power loads throughout

the distribution system.

Conventional Voltage Control

Conventional voltage control is intended to maintain

acceptable voltage profile along a distribution feeder

in accordance with locally available measurements.

Though this often leads to sensible control actions

taken at the local level, this could be suboptimal when it

comes to voltage and reactive power (var) control on a

larger scale. In addition, utilities continually face system

losses from reactive load, or VAR, created by large

customer load devices such as washing machines,

air conditioning units, etc. To address these losses,

utilities have implemented methods to regulate and

reduce the amount of VAR on their systems through

Volt/VAR control (a general term used to describe

different approaches to regulating voltage and VARon distribution feeders). By optimizing voltage and

reactive power, great efficiencies can be realized on

the distribution system. The primary goal of Volt/VAR

control is to minimize the amount of VARs generated

by centralized generation and shipped via transmission

or distribution systems and, in turn, helping utilities

achieve greater system efficiency and increased system

capacity.

Conservation Voltage Reduction (CVR)

The most common smart distribution voltage controlfunction is Conservation Voltage Reduction (CVR)

to intentionally lower the voltage on the distribution

feeder to the lowest acceptable voltage value to reduce

demand and energy consumption.

The ROI for a VVO project could be as short as two

years as a result of cost savings from reduced losses

and reduced generation costs.

Ideally, information should be collected form all voltage

and VAR control devices and acted upon to obtain

optimal consistency with optimized control objectives.

This approach is commonly referred to as integrated

VVO.

VVO is an advanced application that runs periodically

or in response to operator demand and uses two-way

communication infrastructure. VVO makes it possibleto optimize the energy delivery efficiency on distribution

systems using real-time information without causing

voltage/current violations. VVO should work in various

system design and operating conditions.

Technical Challenges

The control variables available to VVO are the control

settings for switchable capacitors and tap changers of

voltage regulating transformers.

VVO is basically an optimization problem due to thefollowing challenges:

Load Sensitivity to the voltage profile

Work by this author has shown that customer load is

sensitive to the voltage profile of the system and that

the load must be modeled accurately to quantify the

impacts and benefits of Volt/var measures.

Discrete(integer) orbinary decision

variables

Nonlinearobjective

High dimensionnonlinearconstraints

Large searchspace andcontrol variables

Many possible solutions are notcontinuous, but rather discrete.Examples:

For a single switchable capacitorbank, the control variable is binary(Out: 0 or In: 1)

For a typical tap changer, the controlvariable is an integer that varies from-16 to +16

Energy loss is a non-linear function

Thousands of powerflow equations

Optimization algorithms need to beefficient and robust for large problems

However, improving the voltage profile (e.g., with

capacitors) can result in an increase in load that may

exceed the loss reduction. Some conventional loads do

not accurately model changes to the system resulting

from changes in the voltage profile.


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TECH ARTICLE


Real-time VVO

New generation of automation control, more robust

bidirectional communication, and a new range of line-

sensing solutions to enable centralized and distributed

control schemes hold a lot of promise for real-time volt-

VAR control for reducing line losses and peak-demand

shaving. By aggregating and analyzing volt and reactive

power real-time data from across the distribution gridoperators can monitor the reliability of the system as

load-profile shifts occur (thus making long-established

power-flow models obsolete). Volt-VAR optimization

programs can also provide another opportunity to boost

returns from installed assets, such as advanced meters.

Closed-loop control schemes, based on real-time data

collection, can enable utilities to dynamically manage

power quality. Utilities can prevent harmful voltage

excursions that inevitably damage and/or reduce

the useful life of equipment. The latest technology

enhancements offered through advanced volt-VARcontrols determine whether devices are turned off or

on by taking real-time measurements and analyzing the

associated VAR flows. This allows utilities to optimize

the system across all feeders served by a substation,

eliminating a situation in which one feeder has a leading

power factor and another has a lagging power factor but

in which the substation bus has met the target power

factor. Innovations in volt-VAR management technology

are enabling the industry to move closer to maintaining a

consistent power factor across all operating conditions

Centralized and Distributed VVO Intelligence

Centralized intelligence allows the management of

the grid on an overall substation level to maximize

efficiency. Centralized intelligence can be layered

over distributed intelligent controls. Such an approach

eliminates vulnerability to a single point of failure, such

a communication failure which may cause the system

to lose all functionality. In a layered system, and in

the event that communications are lost, the system

would continue to function as a result of the distributed

intelligence, albeit, at less optimal level.

VVO Coordination with Other DA Technologies

Volt-VAR can be layered in with self-healing and

distributed energy management systems. This could to

provide addition layers of intelligence that will improve

voltage and VAR support under different operating

conditions and system topology changes.

VVO Requirements

For VVO to operate properly, it is necessary to assure

that the optimal quantity, sizing and placement of

capacitors and regulators across individual feeders.

Intelligent controls and communications, as well as

central analytical software are then added to into the

system.

VVO with Distributed Generation

Advanced volt-VAR control systems are needed to

manage the effects that renewable energy resources,

plug-in EVs and photovoltaics on the grid. These have

the potential of dramatically changing a systems voltage

profile, affecting the quality of service. Having analytics

and sensing and a number of voltage monitoring points

will create a real-time view of a systems voltage profile

on the system with such devices. Because voltage is

managed within tight ANSI norms, the accuracy of the

sensing data is important . Communication bandwidthand low latency are also vital factors for obtaining quality

data in real time for correct control decisions. It is also

important to have sufficient voltage-regulation devices

on the feeders, whether these are capacitor banks or

line voltage regulators to deal with the intermittency of

some of the devices.

About the Author

Nicholas Abi-Samra has been actively involved in IEEE

for more than 35 years. As Vice President of Asset

Management at Quanta Technology, he and his teamhelp utilities better manage and modernize their assets

at lower total lifecycle cost. He was both General Chair

and overall Technical Program Coordinator for the 2012

IEEE Power & Energy Society General Meeting.

Part 1 of a 3-part series...


22/30

Low Voltage ORing FET Controller

ISL6146The ISL6146 represents a family of ORing MOSFET controllers

capable of ORing voltages from 1V to 18V. Together with suitably

sized N-channel power MOSFETs, the ISL6146 increases power

distribution efficiency when replacing a power ORing diode in high

current applications. It provides gate drive voltage for the

MOSFET(s) with a fully integrated charge pump.

The ISL6146 allows users to adjust with external resistor(s) the

VOUT - VIN trip point, which adjusts the control sensitivity to system

power supply noise. An open drain FAULT pin will indicate if a

conditional or FET fault has occurred.

The ISL6146A and ISL6146B are optimized for very low voltage

operation, down to 1V with an additional independent bias of 3V

or greater.

The ISL6146C provides a voltage compliant mode of operation

down to 3V with programmable Undervoltage Lock Out and

Overvoltage Protection threshold levels

The ISL6146D and ISL6146E are like the ISL6146A and ISL6146B

respectively but do not have conduction state reporting via the

fault output.

Features ORing Down to 1V and Up to 20V with ISL6146A, ISL6146B,

ISL6146D and ISL6146E

Programmable Voltage Compliant Operation with ISL6146C

VIN Hot Swap Transient Protection Rating to +24V

High Speed Comparator Provides Fast


23/30

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24/30

EEWeb PULSE


RIGOL

DSA-815

SpectrumAnalyzer

Review of the

Chris AndersonEMC Engineer, Lab Manager


25/30

PRODUCT REVIEW


In this review, I will be looking at this Rigol DSA-815 Spectrum

Analyzer, it covers a frequency of 9 khz to 1.5 ghz. One of the first

things youll notice when you take it out of the box, is that its relatively

small, especially for a spectrum analyzer. Yet despite its small size

it actually has some heft to it. It gives you a very good feeling about

the build quality.


26/30

EEWeb PULSE


Here are some of the features and specs:

- 9 kHz to 1.5 GHz Frequency Range

- Typical -135 dBm Displayed Average Noise Level

(DANL)

-80 dBc/Hz @10 kHz offset Phase Noise

- Total Amplitude Uncertainty


27/30

PRODUCT REVIEW


even if you go over to another

menu youll know that its on, and

here you see the pass band of my

filter (Figure 3).

If I then go in and want to

determine what that pass band

actually is I can turn on some

markers, and I can set thismarker over here, lets say right

about here lets say thats the

pass band. It might not be the

exact 3db point, but itll be close.

Lets add another marker, and

lets put that marker over here at

about the same amplitude, and

well say that thats about our

pass band. And if I want to say,

okay what is my actual marker,

without actually switching

between them, then I can come

down here and I can turn on my

marker table, and youll see that

its about 925.5 mhz to 967.5 mhz,

and youll see those amplitudes

updating in real time.

If I want to let the analyzer settle,

so that I can account for any

noise (or anything else that is

being generated) to get a goodreadout, I can come in here and I

can change my trace from clear

right to max hold, and that will

retain the greatest value at each

frequency point as the analyzer

sweeps.

If I clear that menu off I can see

that its starting to settle in, and

it looks like I did an ok job

picking those points. But maybe

I want to know if I really got a3db point, so I can add another

marker, which Im going to

send to the peak, so that ones

coming in at negative 23.63 db.

Im actually setting at about 5

db down, I could go in and dial

in those markers if I needed to,

but I think this demonstrates the

point.

Figure 1: DSA-815 with Signal

Figure 2: DSA-815 Zoomed on Signal

Figure 3: DSA-815 Tracking Generator


28/30

EEWeb PULSE


Here are a couple other images of the spectrum analyzer:

Figure 4: DSA-815 Side View

Figure 5: DSA-815 Back of Instrument


29/30

PRODUCT REVIEW


Of course, one of the things you have to consider when

youre buying an analyzer is the price. I think the Rigol

DSA-815 will be hard to beat in that category. The base

price is $1,295, and if you need the tracking generator

thats a $1,495 starting price for the entire unit, so its a

$200 add-on.

I think if you evaluate the DSA-815 against its

competitors, as long as the DSA-815 meets your needsfrom a frequency range and noise level perspective, it

would be pretty hard to beat on value. I know a lot of the

larger manufacturers dont even compete in that price

range. When I saw it and I saw the price, I didnt know

what to expect when I pulled it out of the box. But Ive

been very impressed and I think its a wonderful value

I think if you get to play with one yourself youll be very

pleased.

To watch the full video review of the Rigol DSA-815, visit the EEWebYouTube page by clicking the image below:
http://www.youtube.com/watch?feature=player_embedded&v=ZvMFXnkk4PY


30/30
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