WSAT Online Tool for Assessment of Secure Level of Wind Generation on the System

Transcription

1 WSAT Online Tool for Assessment of Secure Level of Wind Generation on the System Dr Ivan Dudurych Load, MW Load, MW 06/10/2006 Load, MW 29/09/2006 Wind, MW 06/10/2006 Wind, MW 29/09/ Wind, MW :00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 0

2 Irish Power Systems Confidential NEX TP LANETFS06 Jul06 Rep ublic of Ir eland Forecast Statement Northern Ireland based on Seven Year Statement Printed:- 08 October 2008 Generation: 1,800 MW installed excluding wind 220 MW wind (approx) 1,960 MW total installed Generation: 6,450 MW installed excluding wind 1080 MW wind (increasing) 7,520 MW total installed Load: varies from 1,735 MW to 5,042 MW Load: Peak 1,719 MW

3 Interconnection Ireland Northern Ireland Double-circuit AC 275kV 2 AC 110kV Further interconnection proposed Northern Ireland Britain 500MW HVDC undersea double pole cable Ireland Britain 500MW HVDC to be owned by EirGrid due 2012, IMera 350 MW Tie-lines now DC

4 How the wind effects frequency control? 1. By night when less responsive plant is online During the morning load rise, when system demand is increasing rapidly MW At the random periods with high wind variations :00 01:30 03:00 04:30 06:00 07:30 09:00 10:30 12:00 13:30 15:00 16:30 18:00 19:30 21:00 22:30 Wind Load

5 Wind Affects Frequency 5sec frequency fluctuations from 3am to 6am No wind 24 February average 14 MW 0.04 Moderate wind 29 Sep average 129 MW 0.04 Frequency fluctuations, Hz Frequency fluctuations, Hz Wind power fluctuations, MW Wind power fluctuations, MW High wind 6 Oct average 420 MW 0.04 High wind 28 March average 866 MW 0.04 Frequency fluctuations, Hz Frequency fluctuations, Hz Wind power fluctuations, MW Wind power fluctuations, MW

6 Disconnections of wind farms due to low voltage

7 Under-frequency wind farm trips :30 17:35 17:40 17:45 17:50 17:55 18:00 18:05 18:10 18:15 18:20 18:25 18:30 Wind output, p.u. Enercon TSO Connected Vestas, TSO connected Bonus, TSO Connected GE, DSO Connected Frequency, Hz Hz 48.3

8 Frequency nadir during conventional unit drop Frequency deviation, Hz % 10% 20% 30% 40% 50% 60% 70% 80% Instant wind penetration, % Hystorical Current max instant wind generation % Contracted load shed Avarage frequency deviation on 260 MW drop Historical max instant wind generation during unit trip % Maximum frequency deviation on 260 MW drop First stage of emergency load sheding Average Frequency deviation on 500 MW drop Historical ΔF, Hz Maximum frequency deviation on 500 MW drop

9 How Much Wind Can be on the System? Maximum wind generation is equal to Load - Minimum controllable generation Minimum controllable generation needed to insure frequency regulation voltage control reserve requirements including extra reserve for wind system stability Morning Load Rise (MLR) Wind might be needed to curtail before the beginning of the morning load rise to ensure adequate ramping capability during the MLR to allow for wind drop off during MLR

10 Wind Control: Night Valley :00 01:30 03:00 04:30 06:00 07:30 09:00 10:30 12:00 13:30 15:00 MW 16:30 18:00 19:30 21:00 22:30 Wind Load

11 :00 01:30 03:00 04:30 06:00 07:30 09:00 10:30 12:00 13:30 15:00 16:30 MW 18:00 19:30 21:00 22:30 Wind Control: Night Valley Wind Load Min Plant

12 :00 01:30 03:00 04:30 06:00 07:30 09:00 10:30 12:00 13:30 15:00 16:30 18:00 19:30 MW 21:00 22:30 Wind Control: Night Valley Curtail Wind Load Min Plant Min+Wind

13 Wind Summary display in NCC

14 Wind Power Stations Controls in NCC

15 Wind Dispatch User Interface in NCC

16 WSAT Overview Wind Security Assessment Tool (WSAT) is an on-line application to monitor voltage stability and transient stability of a power grid under the increase of wind generation Based on Powertech s VSAT and TSAT tools Integrated with EIRGRID EMS through Powertech s DSA Manager tool Analysis can be performed for real-time and forecast system conditions captured by SCADA and solved by SE EIRGRID transient and voltage stability criteria are implemented N-1 contingencies are applied 2 transfers for wind increase are analyzed Cluster-based transfers are used for relieving overloads SPS actions are included in the analysis

17 Power Transfer All scenarios use the same transfer of power transaction. The SOURCE is Wind Generation the SINK is Conventional Generation. Wind Generation Conventional Generation Thus any increase/decrease in Wind Generation (the source) must be met by a corresponding decrease /increase in Conventional Generation (the sink).

18 Voltage Stability Voltage stability is concerned with the ability of a power system to maintain steady acceptable voltage at all buses under normal and abnormal condition A system enters a state of voltage instability when a disturbance, increase in load, or change in system condition causes a progressive and uncontrollable decline in voltage Voltage Security Assessment Tool (VSAT) This is a voltage stability analysis program and can be configured for either off-line or on-line applications Includes many modeling and analysis functions for voltage stability analysis WECC July 2, 1996 event

19 Transient Stability Transient stability includes requirements of voltage stability. It also requires that conventional synchronous machines maintain angular stability of synchronous plant (do not slip poles) and that squirrel-cage induction machines return to nominal speed after contingency events. A system enters a state of transient instability when a disturbance, increase in load, or change in system condition causes a progressive and uncontrollable increase of synchronous machine internal angle, increase in squirrel-cage induction Generator speed (Hz) machine speed, or decline in voltage Transient Security Assessment Tool (TSAT) This is a transient stability analysis program and can be configured for either off-line or on-line applications Includes modeling and analysis functions for electromechanical phenomena Time (sec)

20 WSAT Architecture Hardware View User s workstations Application Administrator: access DSA Manager on WSAT Clients directly or through terminal service General users: DSA Monitor + Off-line PSAT/VSAT/TSAT Ethernet EMS Data server Data server hosts Computation servers WSAT client(s) WSAT servers (as needed)

21 WSAT Architecture Software View User s workstation Off-line TSAT/VSAT/PSAT DSA Monitor EMS LAN DSA Manager WSAT client Data Corporate LAN Data server TSAT Client DSA Service VSAT Client Wind Forecast WSAT servers TSAT Server TSAT Server VSAT Server VSAT Server

22 Engineer Console Messages from WSAT Messages from TSAT engine Messages from VSAT engine WSAT session control Client and server monitor

23 WSAT Controls Available Only To Administrator Real-time system configuration Scenario definition WSAT session control

24 WSAT Controls Available To All Display & Tools Configuration Display & tools configuration

25 WSAT Operator Console Detailed result analysis tools Basecase analysis summary WSAT case browser Transfer analysis summary

26 Controls Available To All Users Case Browser Go to the latest case Browse history cases Hold result display while examining results of a case

27 Basecase Analysis Summary The following information is available Security status: either secure or insecure Security trend (compared with previous case in terms of # of insecure ctg): Improved Worsen Unchanged Unavailable Security violations: for WSAT, only voltage Collapse is enable. Other criteria such as Voltage, Thermal, etc. can also be enabled if required Insecure contingency table

28 Transfer Limit Summary Limits The following information is available Scenario title: Merit ScaleUp Base Value (MW): value of the independent variable in base (real-time) powerflow. The background turns red if the system is insecure at the base case condition Limit Value (MW): value of the independent variable at overall stability limit The background turns red if system if no secure limit could be found. Limit trend: this is similar to basecase security trend, measured by stability limit Details dialog button: opens Transfer Limit Details dialog (explained later) Limiting factor: blank (no problem to reach specified transfer target), insufficient dispatchable reserve, pre-contg, or limiting contingency

29 Transfer Limit Summary VSA/TSA Analysis Results The following information is available Limit (MW): value of the independent variable at the VSA/TSA stability limit. This lower of the two is equal to the overall stability limit. The background turns red if no secure limit could be found Limit trend: this is similar to limit trend, measured by voltage stability limit Security violations: shows VSA/TSA security which are enabled and reason(s) for limit The background of a criterion turns red if it limits the transfer Dispatch refers to the maximum amount of dispatch specified for the transfer. When this is reached, its background turns white Stability bar: explained in the next slide

30 Transfer Limit Summary Stability Bar This is used to indicate the stability limit (independent variable is shown) There are two ways to display the stability bar Display actual MW limit: shown here Display % limit margin: values shown in percent of limit Interpretation of the stability bar (when displaying MW limit) For forward limit search Stability Limit VSA only: first insecure point Base operation point at left For backward limit search Green slice indicates secure point found Base operation point

31 Transfer Limit Details Same information as in transfer limit summary System dispatch status at the stability limit RA actions (if found) when security criteria are violated Outputs of generators in independent variable at the base case condition Outputs of generators in independent variable at the stability limit condition

32 VSAT Viewer For every completed case, all analysis results from VSAT can be examined in DSAOA by clicking on the VSAT Viewer button All DSAOA features are supported, for example, plotting P-V curves

33 TSAT Viewer For every completed case, all analysis results from TSAT can be examined in DSAOA by clicking on the TSAT Viewer button

34 WSAT Transfer Summary All transfers are shown Columns shown can be customized (right-click on column-header)

35 WSAT Result Histograms For all completed case in a specified time period, VSAS result history can be examined by clicking on the History button as shown Base case security histograms Transfer limit histograms

36 05-Tue 11:00 05-Tue 12:00 WSAT output graphs - project Secure Wind Generation Level Asessment Sun 12:00 03-Sun 13:00 03-Sun 14:00 03-Sun 15:00 03-Sun 16:00 03-Sun 17:00 03-Sun 18:00 03-Sun 19:00 03-Sun 20:00 03-Sun 21:00 03-Sun 22:00 03-Sun 23:00 04-Mon 00:00 04-Mon 01:00 04-Mon 02:00 04-Mon 03:00 04-Mon 04:00 04-Mon 05:00 04-Mon 06:00 04-Mon 07:00 04-Mon 08:00 04-Mon 09:00 04-Mon 10:00 04-Mon 11:00 04-Mon 12:00 04-Mon 13:00 04-Mon 14:00 04-Mon 15:00 04-Mon 16:00 04-Mon 17:00 04-Mon 18:00 04-Mon 19:00 04-Mon 20:00 04-Mon 21:00 04-Mon 22:00 04-Mon 23:00 05-Tue 00:00 05-Tue 01:00 05-Tue 02:00 05-Tue 03:00 05-Tue 04:00 05-Tue 05:00 05-Tue 06:00 05-Tue 07:00 05-Tue 08:00 05-Tue 09:00 05-Tue 10:00 On-line Secure Wind Actual Wind Wind Forecast Off-line Secure Wind MW

37 WSAT output graphs - real case

38 Conclusions Wind power integration to grid is a complex task. Constantly increasing level of wind power generation increases risk of instability. Wind power output control is needed and is being implemented. WSAT will help to estimate the optimum amount of wind on-line and indicate the secure level of wind for forecast cases.

39 Thank You! Questions?