Ancillary Service (on a commercial basis)

vertical-integrated unbundled market - liberal

flexibility

active power

reactive power

voltage angle, syst. frequency

voltage module

produce Q, |U| rise;

consume/ absorb Q, |U| drops

security of system operation

Transmission Load Relief (TLR)

Power Transfer Distribution Factors (PTDF)

Pareto

voltage stability

+- 10%

ISO, TSO/ DSO

Exercise topics

transmission line currents

frequency fluctuation

synchronism

bilateral agreement

pool market mechanism

energy reserve

black-start capability

Congestion management

Frequency control

primary control/ local

secondary control/ load following / centralised & coordinated

droop control

Nash equilibrium

ch2- optimal single power plant generation w/
constraints

service quantity, spot price, power dispatch profile, cost & revenue, marginal cost, operation cost &profit,

ch3- Plant operation w/ optional contracts

ch4-optimal dispatch for two plants

pool market trade, spot price, CfD,

biding strategies:
pareto optimum, nash equilibrium

ch5- Transmission Load Relief (TLR)

unconstrained/ constrained eco dispatch, LMP

review contract types

review biding strategies: pareto optimum, nash equilibrium with payoff table

practice!

review LMP, TLP,

redispatch to control power flows in grids

rotor angle stability

congestion at line/ transformer occurs when current exceeds its thermal limits

cascading outage on the devices may occur until complete blackout

loads increase suddenly, freq drops due to the taken kinetic energy from sync gen. rotors

speed governors of generators run against

to recover the reference freq

facilities

reactive compensation devices, transformers(tap-changing& phase shift), Flexi AC Transmission Systems (FACTS), grid topology changes

HOWEVER, it can not help to control the freq. due to load variations!

provision through market

dedicated to preventive or curative issues

prevent freq. collapse

Gen. w/ AVR or PSS

(contribution) AVR: sync. torque; PSS: damping torque

unique buyer: ISO, GenCos & interruptible loads are sellers

long-term contracts

Thermal units: hydro- diesel/ gas turbine gens. w/ limited contribution to the flexibility of volt/ freq stability

short-term contracts

spinning reserve (gens. in)

Cold energy reserve (gen. out)

Service Charges

balancing market

service charge for the users (if any)

transmission services