Smart Places and Infrastructure · Study deck

Smart Grid: Communications and Operations

A utility can see a growing number of meters, substations, chargers, and flexible loads, but those devices do not share one timing or reliability need.

Ada is your guide for this deck.

applicationdomainssmart

Ada, the module guide, in a scene from this chapter.

After studying this chapter

Learning objectives

You will be able to:

match smart-grid communication requirements to standards and duties
evaluate flexible-load and transformer impacts with stated limits
plan grid investment, cyber boundaries, and recovery evidence
Explain: The rows separate the business application from the protocol that carries control, and from the device data underneath.

Major section

Critical Standards Ecosystem

The rows separate the business application from the protocol that carries control, and from the device data underneath.

Once both are fixed, each standard has one place to sit.
DLMS and COSEM land in metering because they define what a register means.
A protocol argument is often a column argument in disguise.

Smart Grid Standards Ecosystem by Layer and Function

Major section

EV Charging and Grid Integration

With the measurement stack in place, the next stress test is load flexibility.

EVs show why a grid-IoT system must coordinate customers, devices, tariffs, and transformer limits at the same time.
Challenge: A single Level 2 EV charger (7.2 kW) can double a home's peak demand.
A neighborhood with 20% EV adoption could overload distribution transformers designed for pre-EV loads.

A Level 2 home charger is both a networked endpoint and a substantial fixed electrical load. The enclosure, branch circuit, cable reach, connector storage, and installation position are part of the deployment; the scheduling and V2G logic above only becomes useful after that physical contract is safe. Photo: Ken Fields, CC BY-SA 2.0

Major section

EV Charging and Grid Integration (continued)

Opportunity: Smart chargers can defer charging to off-peak hours, participate in demand response programs, and even provide vehicle-to-grid (V2G) services that return stored energy during peak demand.

The cable is heavy and long, and where it coils decides whether the unit can serve a car parked either way round.
The holster in the middle keeps the connector off the ground, and the lit ring around it is the only status the owner sees without opening an app.
Behind the case sits a fixed connection to a dedicated circuit, and that is the part which adds 7.2 kW to the house.

EV Charging Integration: Unmanaged vs Smart Charging vs V2G

Major section

Voltage/VAR Optimization (VVO)

Transformer taps change voltage and capacitor banks manage reactive power before the result is measured again.

In the chapter example, reducing 120 V to 116 V gives (120 − 116) ÷ 120 × 100 = 3.3% voltage reduction.
The setting remains within the stated standard, and resistive loads may use 2–4% less energy.
Verification closes the loop: savings count only while power quality and equipment performance remain acceptable.
Most resistive loads (heating, incandescent lighting) consume less power at lower voltage without affecting performance.

Voltage/VAR Optimization (VVO) Closed-Loop Control Process

Major section

Critical Infrastructure Cyber

Smart grid IoT systems support critical infrastructure, but NERC CIP standards apply to specified Bulk Electric System cyber systems and responsible entities, not every grid IoT device.

A successful cyberattack could cascade into widespread blackouts affecting hospitals, water treatment, financial systems, and emergency services.
NERC CIP provides a compliance floor for assets and entities within its defined scope.
The Ukraine 2015 evidence shows why recovery also belongs in the design: remote compromise affected about 230,000 customers for up to six hours, and restoration required manual intervention.
Defense in depth must therefore preserve a trusted way to operate when remote systems fail.

Layered diagram showing smart grid cybersecurity controls: perimeter defenses (firewalls, DMZ), network segmentation (OT/IT separation), endpoint protection (device authentication), and monitoring (intrusion detection, SIEM). Shows NERC CIP compliance requirements at each layer. — Smart Grid Cybersecurity Defense-in-Depth Architecture

Major section

Smart Grid, HEMS, and Stakeholder Boundaries

A smart grid makes electrical power and operational information flow in both directions.

A smart meter can measure imports and exports, but a home energy management system (HEMS) is the local decision boundary that combines meter data, tariffs, appliance constraints, rooftop generation, storage state, and occupant consent.
It may recommend or schedule a flexible load; it must not pretend that every appliance, battery, vehicle, or resident is equally controllable.
A cloud service may coordinate across those domains, but it does not inherit the authority or safety responsibility of the field controller.

Deck summary

Key takeaways

The rows separate the business application from the protocol that carries control, and from the device data underneath.

With the measurement stack in place, the next stress test is load flexibility.
Opportunity: Smart chargers can defer charging to off-peak hours, participate in demand response programs, and even provide vehicle-to-grid (V2G) services that return stored energy during peak demand.
Transformer taps change voltage and capacitor banks manage reactive power before the result is measured again.
Smart grid IoT systems support critical infrastructure, but NERC CIP standards apply to specified Bulk Electric System cyber systems and responsible entities, not every grid IoT device.

Retrieval practice

Recall check 1 of 5

Ada says: answer from memory, then check your reasoning.

Q1A utility needs to send demand response signals to residential customers. Which protocol is designed specifically for this?

AOpenADR 2.0

BModbus TCP

CDNP3

DIEC 61850

Show answer

Answer: A Demand response asks customer-side equipment to adjust consumption in response to utility events.

Retrieval practice

Recall check 2 of 5

Ada says: answer from memory, then check your reasoning.

Q2A neighborhood of 5 homes shares a 25 kVA transformer. Assume each home reaches a coincident 12 kW peak at unity power factor. If 3 homes simultaneously add Level 2 EV chargers (7.2 kW each), what happens to transformer loading?

AThe transformer immediately fails

BLoading stays within normal limits

CLoading increases marginally but remains safe

DLoading increases from 2.4x to 3.3x rating (overload risk)

Show answer

Answer: D This is a worst-case coincident demand comparison, not a prediction of continuous loading.

Retrieval practice

Recall check 3 of 5

Ada says: answer from memory, then check your reasoning.

Q3What is the primary function of capacitor bank switching in VVO systems?

AManage reactive power (VARs) to optimize voltage levels

BGenerate electricity during peak demand

CStore energy for later use

DIncrease power consumption

Show answer

Answer: A Automatic capacitor switching adjusts VAR support along a feeder.

Q4In the cited AEP Ohio field test, Voltage/VAR Optimization (VVO) reduced energy use and demand by:

A0.1-0.5%

B2-4%

C15-20%

D50%+

Show answer

Answer: B VVO coordinates voltage reduction and reactive power support.

Retrieval practice

Recall check 4 of 5

Ada says: answer from memory, then check your reasoning.

Q5What combines trusted grid state with policy before dispatching flexible load or a relay?

AOperations and Flexible-Load Control

BGrid Measurement and Protection

CTrusted Grid Communications

Show answer

Answer: A Grid operations combines trusted state with limits and policy before dispatching a relay, DER, EV charger, or demand-response action.

Retrieval practice

Recall check 5 of 5

Ada says: answer from memory, then check your reasoning.

Q6A utility wants to observe a short voltage sag. Its PMUs sample 30 times per second; its SCADA path polls every 4 seconds. What observation advantage does the PMU stream offer?

APMUs use less bandwidth than SCADA systems, reducing communication costs

BSCADA cannot measure voltage at all, only current and power flow

CSub-second events like cascading failures propagate faster than SCADA can detect

DPMUs are required by NERC CIP regulations while SCADA is not

Show answer

Answer: C The PMU interval is about 33 ms, compared with the stated four-second SCADA poll.

Print reference

Answers 1 of 2

Answer key.

A · Demand response asks customer-side equipment to adjust consumption in response to utility events.
D · This is a worst-case coincident demand comparison, not a prediction of continuous loading.
A · Automatic capacitor switching adjusts VAR support along a feeder.
B · VVO coordinates voltage reduction and reactive power support.
A · Grid operations combines trusted state with limits and policy before dispatching a relay, DER, EV charger, or demand-response action.

Print reference

Answers 2 of 2

Answer key.

C · The PMU interval is about 33 ms, compared with the stated four-second SCADA poll.