1 PCT Messaging Design CEC Title 24 Reference Design.

1

PCT Messaging Design

CEC Title 24 Reference Design

3

1. Introduction..................................................................................................4 1.1 The Title 24 PCT Code Language (Rev 29c) ................................................................. 4 1.2 The Virtual Operation Model for Thermostats ............................................................... 6

1.2.1 Required Functional Resources................................................................................................................................7 1.2.2 Required Functional Behavior..................................................................................................................................8

2. The HVAC System Interface.....................................................................11 2.1 Minimal Direct Control Interface ................................................................................. 11 2.2 Advanced Thermostat Direct Control Interface............................................................ 12 2.3 Digital Control Interface ............................................................................................... 13

3. Expansion Interface ..................................................................................15

4. Communications Interface........................................................................17 4.1 Logical Information and Transaction Model ................................................................ 17 4.2 PCT Functions .............................................................................................................. 18 4.3 PCT Messages and Attributes ....................................................................................... 18

4.3.1 Event Modes...............................................................................................................................................................19 4.3.2 Common Data Classes .............................................................................................................................................19 4.3.3 Message Commands for Minimum Title 24 PCT Functionality........................................................................21

4.4 PCT Transactions .......................................................................................................... 23 4.5 Implementation Profiles ................................................................................................ 25 4.6 Security ......................................................................................................................... 25

4.6.1 Fundamental, Strategic Objectives........................................................................................................................25 4.6.2 Assumptions................................................................................................................................................................25 4.6.3 Risk Management Approach ...................................................................................................................................27 4.6.4 Possible Attacks.........................................................................................................................................................27 4.6.5 Non-Cryptographic Mitigation Methods...............................................................................................................29 4.6.6 Cryptographic Mitigation Approaches..................................................................................................................31 4.6.7 Analysis.......................................................................................................................................................................34 4.6.8 Next Steps...................................................................................................................................................................34

5. Human-Machine Interface ........................................................................36 5.1 Terminology.................................................................................................................. 36 5.2 Next Steps and Issues to be Resolved ........................................................................... 37

5.2.1 Interaction with “Hold” Functions........................................................................................................................37 5.2.2 Recovery from “Off” State within an Active Event.............................................................................................37

5.2.3 Standardization of Colors, Indicators, and Icons 37

4

1. Introduction..................................................................................................4 1.1 The Title 24 PCT Code Language (Rev 29c) ................................................................. 4 1.2 The Virtual Operation Model for Thermostats ............................................................... 6

1.2.1 Required Functional Resources................................................................................................................................7 1.2.2 Required Functional Behavior..................................................................................................................................8

2. The HVAC System Interface.....................................................................11 2.1 Minimal Direct Control Interface ................................................................................. 11 2.2 Advanced Thermostat Direct Control Interface............................................................ 12 2.3 Digital Control Interface ............................................................................................... 13

3. Expansion Interface ..................................................................................15

4. Communications Interface........................................................................17 4.1 Logical Information and Transaction Model ................................................................ 17 4.2 PCT Functions .............................................................................................................. 18 4.3 PCT Messages and Attributes ....................................................................................... 18

4.3.1 Event Modes...............................................................................................................................................................19 4.3.2 Common Data Classes .............................................................................................................................................19 4.3.3 Message Commands for Minimum Title 24 PCT Functionality........................................................................21

4.4 PCT Transactions .......................................................................................................... 23 4.5 Implementation Profiles ................................................................................................ 25 4.6 Security ......................................................................................................................... 25

4.6.1 Fundamental, Strategic Objectives........................................................................................................................25 4.6.2 Assumptions................................................................................................................................................................25 4.6.3 Risk Management Approach ...................................................................................................................................27 4.6.4 Possible Attacks.........................................................................................................................................................27 4.6.5 Non-Cryptographic Mitigation Methods...............................................................................................................29 4.6.6 Cryptographic Mitigation Approaches..................................................................................................................31 4.6.7 Analysis.......................................................................................................................................................................34 4.6.8 Next Steps...................................................................................................................................................................34

5. Human-Machine Interface ........................................................................36 5.1 Terminology.................................................................................................................. 36 5.2 Next Steps and Issues to be Resolved ........................................................................... 37

5.2.1 Interaction with “Hold” Functions........................................................................................................................37 5.2.2 Recovery from “Off” State within an Active Event.............................................................................................37 5.2.3 Standardization of Colors, Indicators, and Icons................................................................................................37

Annex A: PCT Use Cases.............................................................................41

Annex B: Glossary.........................................................................................45

Annex C: UC Berkeley PCT Research Report ............................................47

Annex D: Other Publications.........................................................................48

Annex E: Title 24 Language (Final Draft – Rev 29c)................................49 Annex E: Title 24 Language (Final Draft – Rev 29c)................................49

Annex F: The PCT Vision Document and Related Scenarios.....................51 Eliminating the Need for Rotating Outages through Statewide Air-Conditioning Load Control with Programmable Communicating Thermostats (PCTs) ....................................................... 51 Scenario 1- Residential, Low User, Minimum Functionality, Special Exemptions ................. 55 Scenario 2 - Residential, High User, High End Options, Advanced Functionality .................. 67 Scenario 3 - Large Commercial / Industrial.............................................................................. 73 Scenario 4 – Utility Company................................................................................................... 77 Scenario 5 – California ISO ...................................................................................................... 79 Scenario 6 – California Public Utilities Commission ............................................................... 82

Annex X: Material related to Joint IOU PCT Specifications using Two-Way Communications for Extended Functionality................................................86

Annex X1: Digital Control Interface ........................................................................................ 87 Annex X2: Reliability Event Commands ................................................................................. 88 Annex X3: Message Commands for Joint IOU PCT Functionality using Two-Way Communications ....................................................................................................................... 89 Annex X4: Message Responses for Joint IOU PCT Functionality using Two-Way Communications ....................................................................................................................... 91

5

Introduction

Description of Messages & Data Payloads Required for the CEC Title 24 PCT Specification

Messages Recognize Two Basic System Event ModesPrice EventsEmergency Events.

6

Data Classes for Most MessagesAddressingEvent IdentificationTime Stamping

Event ID ImportanceFacilitate cancellation of eventsPermit multiple event transmissions for

message transport reliability

7

Addressing Scheme Enables Regional or PCT Level FilteringPlace holder for value added information to

facilitate PCT side filtering Two Levels of PCT Operational Status

Visual Indication PossibleUnderlying Physical Communication Layer

e.g. – carrier heartbeatDerived from the last valid message received

Clock Sync Message PCT displays error message if a valid time sync

not received in 24 hr period

8

Price Events

Utility desire to communicate a “super peak rate” period is in effect either by:Simple message that price is in effectExplicit price

Price event message definitionStart and stop time & the price If the price field = zero then a generic super-

peak event with no specific price

9

Consumers PCT has default response to price event, but customer may override programming

PCT Vendors have design flexibility for owner response and / or event & price information

10

Reliability Events

Provides Utilities specific directives to PCT to address reliability Start and Stop TimeAdvance SchedulingReliability Selections

Change Temperature Set Temperature

11

Emergency Event – Special Reliability ClassCoded separately to facilitate expedited

handlingFor example

Normally, PCT events could be cached in area concentrator; then forward when network traffic permits

Area concentrator inspects message header and if emergency detected forwards message immediately with potential auto retransmissions

12

Addressing <ADDR> Common Addressing Information <ADDR>

Attribute Name Attr. Type Explanation M/ O

Data

Source Utility INT8U Utility / DisCo which controls the PCT (Ex: 5=SCE) M

DR Program INT8U Demand response program identifier (Ex: 3=CPP,1=non-curtailable) M

Area / Sub Ident INT16U Locates customer (Ex:0=ALL, 1..999 is area, 1000 up are substation idents M

Feeder Identifier INT8U Feeder number within a substation (0 = all feeders, 1..N = feeder) M

Billing Point Ident INT64U Identifies individual customer (ex: 5 = LADWP) O

Date/Time Stamp <DTIME> Common Date/ Time Information <DTIME>


Data

Year INT16U Ex: 2006 M

Day INT16U Offset from J anuary 01 this year (0..365) M

Second INT32U Seconds since midnight this day (0..86399) M

13

Event Identification <EV_ID> Common Event Identifier <EV_ID>


Data

Event_ID INT16U Message serial number used for event identification and cancellation M

Commands to PCT

Clock Set Clock Set Command


Data

Command Code INT8U Clock set command (ex: 1) M

Address <ADDR> Which PCTs should use this information (this may be ignored) M

Now <DTIME> Present time M

Next_PST/DST <DTIME> Time of next DST/SummerTime shift (ex:2006 302 7200) M

OffsetMinutes INT8S Number of minutes (ex: -60 for USA change away from DST) M

Price Event Price Event Notification


Data

Command Code INT8U (ex: 2) M


Start_Time <DTIME> Event begin time M

Stop_Time <DTIME> Event end time M

Event_ID <EV_ID> Identifier of this price event (used for cancellation) O

Event_Price INT16U $ / KWH * 0.0001 (Ex:2000 = $0.20 / KWH) M

14

Reliability Event – Change Temperature Reliability Event (change temperature) Command


Data





Event_ID <EV_ID> Identifier of this price event (used for cancellation) M

Temp_Change INT8U Amount to change setpoint in tenths of a degree (+ for cooling, - heating) M

Reliability Event – Set Temperature Reliability Event (set temperature) Command


Data






New_Temperature INT16U New temperature setpoint, in tenths of a degree M

15

Emergency Event – Change Temperature Emergency Event (change temperature) Command


Data






Temp_Change INT8U Amount to change setpoint in tenths of a degree (+ for cooling, - heating) M

Emergency Event – Set Temperature Emergency Event (set temperature) Command


Data






New_Temperature INT16U New temperature setpoint, in tenths of a degree M

16

Display Message Display Message Command


Data



Message Length INT8U Number of characters in message M

Message STRING[n] Message to display on display M

Cancel Event Cancel Event


Data



Event_ID <EV_ID> Identifier of this price event (used for cancellation) O

1 PCT Messaging Design CEC Title 24 Reference Design.

Documents

Transcript of 1 PCT Messaging Design CEC Title 24 Reference Design.