PJM2009PJM DOCs #

Reliability Concerns towards Frequency Response

and Overview of BAL 001 and BAL 003

H.W. Herbsleb

Performance Compliance

PJM20092PJM DOCs #

Control Time line for frequency and balancing

2

BALANCING AND FREQUENCY CONTROLExcerpt from : A Technical Document Prepared by the NERC Resources Subcommittee

PJM2009PJM DOCs #

Frequency Performance

Page 3

Arresting Period Rebound Period Recovery Period

Compliance time for Bal-002

PJM20094PJM DOCs #

Different speed of response of responsive units

Page 4

Blue = gas-turbine unit on governor controlRed = (fast) hydro-power unit on governor controlGreen = (ideal) steam-turbine unit on governor control

PJM20095PJM DOCs #

Frequency Response Basics (Using a 1400 MW generation loss event as an example)

Page 5

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Time (Seconds)

Go

vern

or/

Lo

ad

Resp

on

se (M

W)

59.60

59.65

59.70

59.75

59.80

59.85

59.90

59.95

60.00

60.05

60.10

Fre

qu

en

cy (H

z)

Governor Response

Load Response

Frequency

A

B

Cc

NERC Frequency Response =

Generation Loss (MW) FrequencyPoint A-FrequencyPoint B

Slope of the dark green line illustrates the System Inertia (Generation and Load). The slope is P/(D+2H)

Pre Event Frequency

Frequency Nadir:

Generation and Load Response equals the generation loss

Settling Frequency:

Primary Response is almost all deployed

PJM20096PJM DOCs #

Frequency Response Concerns

Frequency Response is declining in Eastern Interconnection

Various factors are influencing

When is frequency response too low?

Primary Control Frequency Response is being withdrawn

Primary inertial generation being supplanted by non-inertial resources wind, solar, electronically coupled resources

What is their response to frequency excursions?

What is their susceptibility to tripping during frequency excursions?

Load characteristics are changing

Unknown frequency response characteristics

Current modeling is insufficient to analyze the phenomenon

6

7Eastern Interconnection Mean Primary Frequency Response Trend

Eastern Interconnection Mean Primary Frequency Response Projected

8

PJM20099PJM DOCs #

Classic Frequency Excursion Recovery

9

Excursion Recovery

A = 60.000

C = 59.812

B = 59.874

59.750

59.775

59.800

59.825

59.850

59.875

59.900

59.925

59.950

59.975

60.000

60.025

60.050

-30 0 30 60 90 120 150 180 210 240 270 300 330 360 390 420

Time (Seconds)

Frequency (Hz)

Recovery Completed, TV

10

Typical Frequency Traces

Following a Unit Trip

11

Inertial Response Variability

Light Inertia

High Inertia

PJM200912PJM DOCs #

Frequency Response Basics

Whys and Wherefores (things to examine)

Deadband currently typical setting is at 36 mHz ERCOT greatly improved frequency response by reducing

deadband to 16.6 mHz

Sliding pressure controls

MW setpoints limited time of response

Blocked governor response

Once-through boilers

Gas Turbine inverse response

12

13

Frequency Response

-150.00

-100.00

-50.00

0.00

50.00

100.00

150.00

59.50 59.55 59.60 59.65 59.70 59.75 59.80 59.85 59.90 59.95 60.00 60.05 60.10 60.15 60.20 60.25 60.30 60.35 60.40 60.45 60.50

Hz

MW

Ch

an

ge

Droop Setting 5.00%

Deadband Setting

Hz600.000

00Capability (MW)

0.036

Close up look at +/-0.036 Hz Dead Band with Step Implementation

600 MW Generator

Step response at dead-band.

PJM200914PJM DOCs #

14

Frequency Response Initiative

PJM200915PJM DOCs #

FRI Objectives

Coordinate all NERC standards development and performance analysis activities related to frequency response and control

Identify specific frequency-related reliability factors

Identify root causes of changes in frequency response

Identify practices and methods to address root causes

Consider impacts of integration of new generation technologies (such as wind, solar, and significant nuclear expansion)

15

PJM200916PJM DOCs #

BAL 001 Requirements

R1-

R2-

R3 - Each Balancing Authority providing Overlap Regulation Service shall evaluate Requirement R1 (i.e., Control Performance Standard 1 or CPS1) and Requirement R2 (i.e., Control Performance

Standard 2 or CPS2) using the characteristics of the combined ACE and combined Frequency Bias

Settings

R4 - Any Balancing Authority receiving Overlap Regulation Service shall not have its control performance evaluated (i.e. from a control performance perspective, the Balancing Authority has shifted

all control requirements to the Balancing Authority providing Overlap Regulation Service).

PJM200917PJM DOCs #

BAL 001 Measurements

M1- Each Balancing Authority shall achieve, as a minimum, Requirement 1 (CPS1) compliance of 100%. CPS1 is calculated by converting a compliance ratio to a compliance

percentage as follows:

CPS1 = (2 - CF) * 100%

The frequency-related compliance factor, CF, is a ratio of all one-minute compliance

parameters accumulated over 12 months divided by the target frequency bound.

M2- Each Balancing Authority shall achieve, as a minimum, Requirement R2 (CPS2) compliance of 90%. CPS2 relates to a bound on the ten-minute average of ACE. A

compliance percentage is calculated as follows:

The violations per month are a count of the number of periods that ACE clock-ten-minutes

exceeded L10.

PJM200918PJM DOCs #

BAAL Field Trial

The purpose of the new BAAL standard is to maintain interconnection frequency within a predefined frequency profile under all conditions (normal and abnormal), to

prevent frequency-related instability, unplanned tripping of load or generation, or

uncontrolled separation or cascading outages that adversely impact the reliability of

the interconnection.

NERC required the balancing authority demonstrate real-time monitoring of ACE and interconnection frequency

against associated limits and

shall balance its resources and

demands in real-time so that its

ACE does not exceed the

BAALs for a time greater than

30 minutes.

PJM200919PJM DOCs #

BAL 003 Requirements

R1- Review and recalculate the Frequency Response of the Balancing Authority Area.

R2- Establish and maintain a Frequency Bias Setting that is close or greater than the Balancing Authoritys Frequency Response.

R3 - Operate its Automatic Generation Control (AGC) on Tie Line Frequency Bias.

R4- Use Dynamic Scheduling or Pseudo-ties for jointly owned units that reflect their respective share of the unit governor droop response in their respective Frequency Bias

Setting.

R5- Balancing Authorities that serve native load shall have a monthly average Frequency Bias Setting that is at least 1% of the Balancing Authoritys estimated yearly peak demand per 0.1 Hz change.

R6 - A Balancing Authority that is performing Overlap Regulation Service shall increase its Frequency Bias Setting to match the frequency response of the entire area being

controlled.