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Flashcards in NERC Prep Deck (233):
1

Area control error

An instantaneous difference between a balancing authorities net actual and scheduled interchange , taking into account the effects of frequency bias and correction for meter error.

2

Contingency reserves

The provision of capacity deployed to meet the disturbance control standard and other nerc and regional reliability organization contingency requirements.

3

Disturbance control standard

The reliabity standard that sets the time limit following a disturbance within which a balancing authority must return its area control error to within a specified range

4

Operating reserve

That capability above firm system demand required to provide for regulation, load forecasting error, equipment forced and scheduled outages and local area protection. It consists of spinning and non spinning reserves

5

Reportable disturbance

Any event that causes an ace change greater than or equal to 80% of a balancing authorities or reserve sharing groups most severe contingency

6

Reserve sharing group

A group whose members consist of two or more balancing authorizes that collectively maintain allocate and supply operating reserves required for each balancing authority's use in recovering from contingencies with the group

7

Disturbance

Nerc required time error to be fixed within 15 mins following a disturbance

8

Contingency reserves

Non spinning or supplemental and spinning reserves

9

Operating reserve

Non spinning , spinning reserves, and regulating reserves

10

Operating reserves contributors

Controllable load reserves, adjustments to interchange schedule, generation

11

Contingency reserve

Covers most servers single contingency , more that 80% - reportable. More than 100% of most severe contingency reportable event but no penalties apply for failure to meet DCS

12

Reportable contingency time

Within 15 mins recover from reportable disturbance, within 90 mins shall fully restore . 90 mins begins at end of 15 min period

13

Balancing authorities shall review contingencies how often to determine single worst contingency?

Annually

14

Contingencies occurring with in how long considered 1 event?

60 seconds

15

A sudden change in balancing authority's demand supply balance following loss of generation results in sudden change in

ACE

16

What group can approve a change in the disturbance recovery period for an interconnection?

Nerc operating committee

17

Contingency reserve restoration period begins at?

The end of disturbance recovery period

18

Frequency bias setting

A value in mw/.1hz set into balancing authorities agc equipment to represent a balancing authorities response to a frequency deviation

19

Pseudo tie

A telemetered reading or value that is updated in real time and used as a tie line flow in the agc ace equation but for which no physical tie or energy metering actually exists

20

1% change in frequency =

2% load change in same direction - primarily of induction motors not heaters ( resistive ) this is used to determine BETA for ace equation

21

Generator response to governor droop

200mw/3hz x (60hz-59.95hz)=3.33mw

22

Frequency response charachteristic

Decrease load/decrease frequency+ generator output

23

Frequency bias = frequency response

x

24

Actual interchange + frequency bias =0 ACE

x

25

Bias setting

Reported to nerc yearly, must be at least 1% of the balancing authorities estimated yearly peak demand per .1hz change as described in the frequency response charachteristic survey training document for a native load serving balancing authority

26

Tie line frequency bias controls

Fixed frequency bias - based on a fixed straight line function of tie line deviation versus frequency deviation. Variable bias- based on a variable function of tie line deviation to frequency deviation

27

Balancing authorities- overlap regulation

ba that are performing overlap regulation service will increase its frequency bias setting to match the frequency response of the entire area being controlled

28

Balancing authorities- supplemental regulation

bA performing supplemental reg service shall not hangs its frequency bias setting

29

Jointly owned units

Frequnecy bias setting is included in the area in which the unit is located only

30

Frequency bias setting

Must be close to areas frequency response. If it is not and is set to low and an external loss of generation occurs, ace will become positive and agc will lower generation , screwing things up even more

31

Tie line frequency bias

Each BA shall operate its AGC on tie line frequency bias

32

Minimum frequency bias setting for generation only balancing authority

1% of its estimated maximum generation level in the coming year per .1 hz change

33

Determining fixed frequency bias

By averaging the frequency response for several disturbances during on peak hours

34

Dynamic schedules

When jointly owned units - each BA shall account for the unit by including their respective share of units governor response charachteristics when calculating frequency bias . Used for the value for interchange accounting purposes

35

Time error correction

Adjust frequency by .02 hz so if it was fast it would be 59.980 or slow is 60.020 or adjust schedule frequency bias setting to + or - 20% of bias setting and take that off of NIs so for example if area had bias setting of 100mw it would add or subtract 20 me to NIs from ace equation

36

AGC

Automatically adjusts a balancing authorities generation from a central location to maintain its interchange schedule plus frequency bias.. Limits change in ACE to maintain a good cOS

37

CPS1

Measures a balancing authorities impact on interconnection frequency

38

CPS2

Measures the ability of a balancing authority to manage unscheduleed flows

39

Regulating reserve

The part of the operating reserve used to keep ace within a reasonable value to comply with CPS standards

40

Flat frequency control

Only used when area is islanded includes only 10b(Fa-Fs) part of ACE equation

41

Ace calculated every

6 seconds

42

Supplemental regulation service

Is a method of providing regulation service in which the balancing authority providing regulation service recieved a signal representing all or a portion of the other balancing authorities ACE

43

Overlap regulation service

A method of providing regulation service in which the balancing authority providing the regulation service incorporates all of the other balancing authorities tie lines, frequency response, and schedules into its own AGC/ ACE

44

Factors contributing to inadvertent interchange

Frequency support , load changes with in balancing authority, generator lag, metering errors, unilateral inadvertent interchange payback, human error

45

NIa

Algebraic sum of all the tie lines with adjoining balancing authorities

46

NIs

Scheduled flow of MW with all of the adjoining balancing authorities

47

Beta

Contribution to interconnection frequency control based on its frequency response charachtertics

48

Secondary/ good inadvertent interchange

Frequency support , regulation, governor support

49

Unilateral payback

Inadvertent interchange accumulations paid back unilaterally to a target of non zero ace, limited to balancing authorities L10 , cannot burden interconnection

50

Inadvertent interchange summaries

Must include at least the previous accumulation , net accumulation for the month, and final net accumulation for both the on peak and off peak periods

51

Frame relay

Data transmission technique used to send digitial info quickly to many destinations from one point of origin

52

Information assets

Proccessed or unproccessed data using nerc net

53

Nerc net

WAN used for exchanging power system info over frame relayit supports intergal security network, interchange distribution calculator, and reliability coordinator information system

54

Alternate pathways for communication

Looping a microwave system.. Redundant paths using different equipent such as protective relaying for transmission line carriers use microwave for one set or relays and power carrier for 2nd set of relays

55

Balancing authority

Integrates recourse plans ahead of time. Maintains load interchange generation with in a balancing authority area and supports frequency in real time

56

Reliability coordinator

The highest level of authority responsible for the reliable operation of the BES

57

Emergency load reduction plans

Must mitigate iROL violation within 30 mins

58

Balancing authority experiencing emergency

Shall only used assistance of interconnections frequency bias for the time needed to implement corrective actions

59

Balancing authority not experiencing trouble

Shall not unilaterally adjust generation to correct frequency problem while outside balancing authority is correcting its problem- it will strain the system plus add unshschuedulrd interchange

60

5% reduction in voltage

Equals overall 3% reduction in inductive and resistive loads

61

2nd steps for balancing authority

Manually shed firm load then request reliability coordinator to declare energy emergency

62

Enery emergency type

1- all available recourses are in use , foresees problems, all sources curtailed2- load management procedures are in effect , designated energy difficient, public appeals, dropping load, 3- firm load is being shed , must complete report and send within 2 business days to reliability coordinator

63

DOE loss of load reporting

Customer load lost,efforts to reduce load, deliberate acts of sabotag, vandalism, cyber attacks initial report due within 60 mins, final done within 48hours with all Events and remedies

64

NERC loss of load report

Same as DoE report but includes , unusual event that occurred to bulk system

Subject to regional reliability organization apprival,Preliminary due within 24 hours, final within 60 days

65

Role of regional reliability organization following a report/ disturbance

Shall make a representative available for preparation and investigation of final report, track and review status of final report recommendations, this should happen twice per year to make sure reccomendations are being acted upon, if any recommendation has not been acted on within 2 years, RRI shall notify Nercplanning committee. -SOS-notes/#sthash.11jXj9fk.dpuf

66

Transmission operators responsible for

Reliability of local transmission system, operates or directs operations of the transmission facilities, provides maintainence schedules, maintains voltage profiles , defines operating limits, develops contingency plans, coordinates load shedding

67

87 relay

Differential relay

68

21 relay

Distance relay

69

67 relay

Directional over current relay

70

Transfer trip signal

Form of pilot relaying, can be sent over fiber optics, microwave etc

71

Distance relays

3 zones of protection

72

System operating limits based on

Facility ratings, transient stability ratings, voltage stability ratings , system voltage limits

73

Voltage collapse

Lack of reactive power, voltage down by 10-20%, not enough mvars to serve power system and loads

74

Getting ahead of voltage

Putting capacitor banks in service before planned outage

75

Other actions to get ahead of voltage

Take shunt reactors out of service, raise generator voltage,raise tap positions on transformers, return lines and generators to service, curtail interchange transactions, curtail or shed load

76

Prevent voltage collapse by

Carrying dynamic reactive reserves close to the load, if mvars are not available shed load, ideally heavy inductive loads

77

Instability

Trans system does not have reserve transmission capacity mw or mvar reserves to handle the loss of a major electrical component such as line or generator

78

Uncontrolled separation

Instability when the power angle between two sections grows to large and the magnetic bond between the two sections is not sufficient to keep generators from losing sychronism

79

N-1

Operating the system to satisfy the most severe single contingency is also referred to as operating to satisfy the most severe N-1

80

TOs operate to protect against

Instability, uncontrolled separation, cascading outages from multiple outages

81

SOL

Must return system to within normal operating limits within 30 mins, transmission operator must take immediate action such as curtailing loads, energy service etc

82

Operational reliability info that balancing authorities provide reliability coordinators with

To be updated every 10 mins.. Example tie lines flows, operating reserves, mw reserve available within 10 minutes

83

Power angle

Difference in voltage angles between two locations in the power system

84

More capacitive circuit

Current will lead voltage which will tend to raise voltage

85

As power angle increases power transfer increases

x

86

Torque angle

Difference in voltage angles between generator internal or excitation voltage and the system voltage

87

Real power flows from

Higher voltage angle to lower voltage angle

88

Real power transfer

The higher the voltage the lower the power angle required for a given power transfer

89

When iROL or sol exceeded for more than 30 mins

Notify nerc and rro

90

Transformers rated in?

MVA

91

Shunt capacitor banks

Supply reactive power to the inductive load, reduce current between generator and load, reduce mvar losses

92

Shunt reactors

Absorb excessive reactive power locally

93

Capacitor

Element that stores energy in the form of electrical charge and introduces capacitance into a circuit . The stored energy creates an electrical field

94

Capacitive reactance

Measure of how a capacitor affects the flow of ac current . It describes the reaction of a circuit to the fluctuating electric fields of ac voltage. A capacitor that is places into an ac circuit builds up a charge that opposes change in voltage

95

Inductance

The property of an electrical circuit that produxes an electromotive force by induction when the current is changing. Inductance opposes current changes

96

Reactive power

The product of voltage and out of phase current , measured in volt ampheres reactive or var.

97

MVA

Consists of 2 different types of power, megawatts and mvar, mw does the actual work or real power... Mvar produces the magnetic field that enables the power to do the work

98

Angular separation or phase angle

Angular seperatipn between current and voltage cycles..in capacitive circuit. Current leads voltage . Inductive circuit is opposite

99

How to raise voltage on a system

Capacitive reactance must me increased or inductive reactance lowered

100

Placing capacitor near inductive load

Reduces current flow and line losses

101

Dynamic sources of reactive power

Transmission lines and generators w auto voltage regulators

102

Knee of pv curve

Once this point is reached . Any increase in mw will cause voltage collapse , to avoid this , redid patch generation or place capacitors inservce closer to the load

103

Ace DCS violation restore time

15 minutes

104

If a transmission operator is in unknown state

He has 30 minutes to restore

105

AGC control types

Pulse control or set point contro

106

Agc pulse contro

Units recieve raise or lower controls every few seconds this pulse acts on a speed changer motor to change its load reference settings in small increments

107

Set point control for agc

Set desired mega watts fed directly to turbine controls- once through fossil units use this

108

Communications

Must be redundant such as looping a microwave system or using redundant paths with different equipment

109

Facilities management

All operators who may need to use backup system should practice with it monthly ,

110

Communications

Coordinated communications include nerc hotline, weccnet, and reliability coordinator information system .. Must have procedures for backup communications

111

Nerc net

A WAN that supports interregional security network, interchange distribution calculator and the reliability coordinator information system

112

Communications and coordination

Each TO and BA shall notify its RC and all other potentially affected TO and BA through pre determined communication paths of any condition that could impact reliability or which could require firm load shedding

113

Voltage reduction customer demand

A 5% reduction in voltage will drop load by 3%

114

Emergency operating agreements between adjacent BAs

1. Provisions for emergency assistance 2. Provisions to obtain emergency assistance from remote BAs

115

If a BA loses its largest generating source

A neighboring BA can change the NIs part of its ace equation to make up for the generation

116

Reserve sharing group

Agreements for emergency assistance minimize the amount of time a bA has to rely on the interconnection for bias support - should only be used to evaluate options and resolve emergencyreturning ACE to normal values as soon as possible is primary objective

117

Transmission operators emergency load reduction plan

Shall have load reduction plan for all IROL that includes facilities in its area. Shall include details of amount of load shedding to be done to mitigate iROL violation before system separation or collapse occurs. Must be done within 30 minutes .

118

Each TO and BA shall develop 4 plans

1.'mitigateoperating emergencies for insufficient generating capacity. 2) mitigate operating emergencies on the transmission system 3) implementation of load shedding when nessasary 4) system restoration

119

TO and BA emergency plans to mitigate operating emergencies

1)communications protocols to be used during emergencies , including assignments to communicate within and external to the organization 2)a list of controlling actions such as starting offline generators etc 3) tasks to be coordinated with other entities such as providing reActive power, voltage control at interconnection 4) staffing levels for emergency. It is important to note that one of the controlling actions shall be load reduction in sufficient quantities to resolve emergency within established nerc guidelines

120

TO and BA emergency plan review

To be done once a year

121

BA anticipating operating emergency

Bring on all avail generation, postpone equipment maintainence , schedule interchange purchases in advance, be prepared to she'd firm load

122

BA not experiencing emergency

Shall not unilaterally adjust frequency during emergency. Will cause overloading of transmission lines and will develop excessive inadvertent interchange accumulation

123

If a BA needs to declare energy emergency

This is done through its RC

124

BA not complying with DCS or CPS

Shall remedy by , loading all available generation , deploying all available operating reserve, interrupting interrupt able loads and exports, requesting emergency assistance through other BAs , declaring an energy emergency though its RC , reducing load through such procedures as voltage reduction, publicappealsand curtailment of interrupt able and firm loads

125

Energy emergency alert levels

Eea1) when a BA or lse foresees a problem sustaining its load eea2) when a BA is no longer able to provide its customers energy requirements , eea3 when firm load shedding is imminent or in progress
CMD

126

Load shedding plans

Shall be coordinated with interconnected BAs and TOs to shed load for under frequency and under voltage . Load shed should be done before generation is shed. Under voltage load shedding occurs in pre selected blocks

127

A BA or TO or LSE experiencing a disturbance

Shall submit a preliminary written report within 24 hours to RRO and NERC and DOE of the disturbance .. If weather does not permit the writing of the report then they should verbally notify the rro and nerc

128

DOE reporting

Initial reporting done within60 mins ,final report done within 48 hours

129

DOE disturbances

Uncontrolled loss of 300mw for more than 15 mins from single incident, load shedding of 100mw during emergency plan, voltage reductions of 3% or more,public appeals to reduce use of electricity, actual or suspected attacks , fuel supply emergencies, loss of electric service to 50k customers for more than am hour, complete operational shutdown of transmission or electrical system

130

Nerc disturbance reporting

Loss of component that affects integrity of the interconnection, interconnection islanding, loss of generation (200mw or more in eastern and 1k I'm ercot), equipment failures that result In firm load loss for 15 mins or more, firm load shedding of 100mw or more to maintain continuity of BES,a violation of IROL , any disturbance that the operating committee wants to submit to the dawg

131

Final report due to nerc

Within 60 days

132

RRO responsibilities during emergency

Make representatives of the nerc operating committee and the dawg available to assist in final report. Track and review status pf reccomendations of report. This should occur at least twice that year

133

TO restoration plan requirements

Personel identified, reliable black start units, contingency plans, synchronizing areas, load restoration including critical loads , procedures for simulating and where practical testing every 3 years, training records showing restoration excersizes, functions to be coordinated with and among RC and neighbors , notifications to operating entities as steps are completed

134

TOP system restoration plans must be

Updated as nessasary to reflect changes and correct deficiencies , reviewed annually, developed w intent to restore interconnection , coordinated w neighboring systems , periodically testing of telecommunications equipent

135

TOP emergency plans as it relates to generation

Emergency power should be available to shutdown safely, operate turning gears, minimize damage to units, maintain communications , expedite restart

136

TO and BA must coordinate restoration actions with

RC

137

How to proceed after islanding or collapse

Determine extent and condition of area, contact other BAs and TOs to determine circumstances in their areas, start taking nessasary actions to restore system frequency by matching generation to load, begin reviewing interchange schedules , reschyronoze the isolated area to surrounding areas only after RC gives their approval, use strongest transmission lines and restore offsite power to nuclear station ASAP

138

Open circuit breakers

On distribution side of blacked out area to control power levels, also disable automatic reclosing relays.

139

Reschyronize with interconnection

Only done at power plant w scope, the phase angle should be less than 10 degrees, frequency should be the same and voltage magnitude close too. If differences are to large, operator can re dispatch generation to reduce differences

140

Self certification

Every year each TO shall self certify to the RRO compliance standard . Shall include : operating instructions for restoring loads , set of procedures for annual review and of possible simulation , documentation of personnel training records to verify training , reporting of any significant changes to restoration plan to the RRO

141

RC has highest level of authority

It is responsible for the coordination of system restoration

142

During restoration RC shall

Establish communications with other RCs the RRO and Nerc via the nerc hotline and the RC'S

143

Each RC is required to sign nerc standards of conduct

Nerc standards of conduct address ...independence , emergency actions, reporting deviations, rules governing employee conduct, books and records,rules governing maintainence of written procedures

144

During restoration

Nominal voltages shall be maintained between 90-110%

145

Shunt capacitor banks during restoration

Should be taken out of service while restoring the system

146

Static var compensators and synchronous condensers during restoration

Should be placed in service as soon as practical

147

Synchronizing of islands

Shall be approved, coordinated, communicated by the RC as to not burden surrounding areas.

148

Back up control centers

Reliability entities are not required to have back up control centers but procedures must be in place if primary control center goes down. Must not burden interconnection

149

Loss of control center contingency plans

Must address .. Ability for instantaneous tie line mw and mvar telemetry.. Ability for instantaneous generating unit telemetry.. Ability to read mw hour accumulators for all tie lines and generating units.. Ability to collect system frequency and time error measurements.. Data links to send generation control signals to generator control centers.. Lost of critical facilities of applicable entities

150

Loss of control center cont.

Must contain procedures for maintaining basic voice communications .. Conduction of annual testing of plan.. Annual training. Review of plan annually.. And updating plan annually

151

Indications of lightening fault

Ground relay operation ( relay 64) or directional current relay (67)

152

Phase to phase fault

Protected by distance relay (21)

153

2 different types of zones for relaying

Open and closed .. Differential protection is example of closed zone.. Distance relay example of open zone

154

Differential relaying

Closed protective zone.. Measures current entering and leaving zone

155

Distance relaying

Open zone... Looks at impudence of line for a specific distance..have quality known as Reach. This tells how far down the line it will detect a fault. If it is set to high it will detect faults to far down line which will cause excess tripping

156

Over current relaying

Used as a backup to distance relaying and differential relaying . Can be directional or non directional ( will only trip of current is flowing 1 way) -

157

Pilot relaying

Protective relaying where relays communicate with each other to allow for faster and more accurate clearing of faults within line segment

158

Transfer trip relaying

Form of pilot relaying.. Initiated at one location and sent via communications channel to trip another breaker or trip auxiliary relay which will trip multiple circuits

159

Misoperation procedures

Each GO TO or anyone that owns a transmission protection system shall provide its RROwith it's misoperation analysis and corrective action according to RRo procedures

160

Operating emergencies

Line overloading .. Loss of transmission line..loss of generation..shortage of reactive power

161

Actions TO takes during energy emergency

Curtailing transmission service.. Curtailing energy schedules. Operating equipment such as reactive sources.. Shedding firm load

162

A system with a generating deficiency

Must reduce its load to restore ace to an acceptable value if they cannot balance generation and load in a timely manner

163

Being prepared for a large system disturbance or pending voltage collapse

Areas must have a program in place to arrest these conditions..should address levels of voltage and frequency at which manual action should be taken.. Also to prevent abnormalities such as over voltage or generation instability caused by automatic load shedding

164

All BAs are required by nerc

To maintain operating reserves

165

Exceptions for burdening neighboring systems

Generator outages- must coordinate with TP...transmission facilities- must coordinate with RC

166

Elevating transmission service priority of an interchange transaction

You can change the priorities of interchange transactions and interrupt power if it will help the energy deficient area the LSE must have RC declare an EEA which must be posted on NERC website and include the expected level of the transmission service priority declaration

167

Daily load forecast is determined by tools such as

Load forecast..unit commitment.. Power flow simulation programs

168

SOLs are based on

Facility ratings ..transient stability ratings.. Voltage stability ratings.. System voltage limits

169

Economic dispatch

Point where all generation is operating at the same incremental cost while serving the demand

170

Transfer capability studies

Should be done between operating entities annually or whenever a change in facilities warrants a new study. All entities should use uniform line identifiers to not get confused

171

Transfer capability issues include

Voltage limits.. Reactive limits.. Thermal limits .. Stability limits

172

GO must provide info on outages for the following day

To TO for any generator greater than 50mw.. TO must provide info daily to RC if generator over 50mw or line over 100kv.. Outage info posted by 1200 cst

173

N-1 contingency

single worst contingency on the system

174

Voltage control equipment outages

Shall be coordinated between entities for AVRs..shunt capacitors etc

175

Voltage collapse

When there is lack of reactive power .. Voltage levels down 10-20%

176

Getting ahead of voltage

When you Know you are going to have a voltage decline. Place capacitors in service, take reactors out.. Raise gen voltage.. Raise transformer tap positions .. Curtail transactions.. Curtail or shed load.

177

When reactive recourses are limited

Limit mw transfers - this prevents power angle increases.. Keep voltage high- this reduces current and angle.. Redid patch generation .. Shift generation patterns to unload heavy loaded lines .. Request neighbor reactive support . Shed load

178

RC is responsible for

Scheduling of potential reliability conflicts

179

Uncontrolled separation can occur as the result of

When power angle gets too large between two sections and the magnetic bond breaks and they loose synchronisim

180

TOs must operate in anticipation of worst contingency

This night be loss of largest unit or large interchange purchase

181

Following a contingency or other event which results in SOL violation

TO must return limits within 30 mins.they must make every effort to stay connected to interconnection but of they deem they are in danger of sol or iROL they can disconnect

182

If TO enters unknown operating status

Must restore system to proven reliable operating status within 30 mins

183

TOs must coordinate with other TOs

Maintain develop and implement procedures to provide for transmission reliability

184

Transmission line capacity is determined by

Thermal limits

185

Transmission line inductive reactance

Dependent upon spacing between strands within each conductor and distance between each conductor

186

Transmission line capacitive reactance

Dependent upon size and spacing of conductors

187

All transmission equipment rated by

Transmission owner..these ratings are used to establish SOLs for system

188

TOs and BAs provide monitoring data to RC

This helps RC to perform reliability assessments .. Coordinate reliable operations within RCa and with other RCs

189

Electric system reliability data is updated

Every 10 mins.. Includes tie line flows generator mw output.. Etc

190

Torque angle

Angular difference between the rotor magnetic field and the magnetic field of the stator of the generator

191

Power angle

The voltage angle difference between 2 locations in the power system

192

Phase angle

The angular separation or difference in phase between the current and the voltage waves

193

RCs publish BA data and system operating assesnements

On the nerc isn or rcis.. BAs provide electric systems reliability data to the RCs via the rcis

194

RC,BA,TO

Shall have access to all info nessasary to balance generation and load including .. Status of generators and transmission recourses.. Protective relay status.. Weather forecast and past loads.. System frequency

195

Sufficient metering and monitoring equipment

Shall be provided to all RC TO and RC

196

3 types of stability

Steady state- no significant changes ... Transient- a sudden large change..... Oscillating - constantly changing voltage frequency and angles

197

Avoid excessive transmission line loading

This results in large power angles.

198

The more transmission lines that are in service

The more power can be transferred at a given torque angle

199

Verify generator voltage regulators are in service

If they are in automatic the higher the voltage the lower the power angle that is required for given power transfer

200

Records must be kept to show

Evidence that TOinformed RC when iROL or sol was exceeded.. There were actions to return system to within limits .. The TO returned system to within an IROL -

201

Each iROL or sol exceeding 30 min

Shall be reported to the RRO and nerc within 72 hours.. Using nerc iROL report

202

Transformers are rated in

MVA..usually have several ratings associated with the stages of cooling

203

Shunt reactor banks

Absorb excess reactive power , usually lightly loaded lines

204

Priority to alleviate violations

Redispatch generation.. Curtain interchange transactions.. Disconnect overloaded equipment.. Shed load


205

Circuit breakers

Usually not limiting component in power transfers due to high continuous rating.. If a CB fault clearing time is too great it can limit power transfers by need for creating stability limit

206

Disconnect switches

Not used to interrupt fault current

207

Air break switches

Limited ability to interrupt load . Limited to small current ineruption such as transformer charging current

208

Shunt capacitor banks

When energized. Produce reactive power.

209

Interchange transactions and schedules may contribute to sol and iROL

Because of parallel flows

210

Increased current cause

Increased loading and larger power angles

211

When TO takes action to alleviate sol or iROL

Must notify RC and effected TOs.. If possible notify before you take action

212

Priority to alleviate violations

Redispatch .. Curtail interchange .. Disconnect overloaded equip.. Shed load

213

Benefits of being connected to interconnection

System inertia from stored energy in rotating generators.. Ability of affected system to resist changes in frequency .. Access to reserves, not only mw but also dynamic reactive reserves.. Instant assistance from tie line bias

214

Synchronizing relays

Need 20 percent power angle or less to tie busses together

215

Collapse

Low frequency .. Low voltage.. High currents

216

Apparent power MVA

Consists of both active and reactive power

217

Increased loading causes

Circuits to be more inductive

218

Voltage control is

Control or reactive power flow

219

When generator AVR is in service

It is considered a dynamic source of reactive power

220

Nerc standard for maintaining reactive reserves

Each TO shall have adequate reactive resources within its area to protect voltage levels under normal and contingency conditions

221

A strong bus

One that has 1 or more generators attached at the closed end of a line that has the ability to absord mvar
/Nerc-SOS-notes/#sthash.fx7ecXpD.dpuf

222

Responsibility of development of emergency load reduction plan to respond to iROL

Transmission operator.. Plan must be able to be implemented within 30 mins

223

An emegency Alert is a

Emergency procedure

224

Nerc has how many emergency alert levels

3

225

Rro final reports are due within

60 days

226

A reportable incident shall be reported to

Nerc and rro

227

Doe reports are aimed at

Customer load loss, sabotage, and efforts to reduce load

228

Rescynchronising of major system islands should only be attempted after approval by the

Reliability coordinator

229

Audit of loss of primary control center plan is conducted

Every 3 years

230

Loss of primary control center plan must be implemented within

1 hour

231

Distribution providers and load serving entities take reliability directives from

Transmission operator

232

Balancing authority is required to maintain

Operating reserves

233

Angle instability

Is the inability for system to maintain magnetic bonds