Synchrophasor: Implementation,Testing & Operational Experience Uttam Mishra Doble Engineering Company

Operational Experience Presentation Topics What is SynchroPhasor Applications Testing PMUs Operational Experience Conclusion

Phasor Measurement Unit Definition : Phasor Phasor is a vector which has magnitude and angle Corresponds to a sinusoidal waveform θ

Phasor Measurement Unit PMU typical configuration:

Phasor and Synchro Phasor Time aligned Phasor : Synchro Phasor GPS satellites provides time stamp Time aligning helps to analyze system events G Zs 21 θ

Total Vector Error Error Expected Phasor Actual Phasor Ref 𝐓𝐕𝐄 % = Length of Error Phasor Length of expected Phasor In illustration, actual phasor is off in both magnitude and angle. 1% TVE ≈ .573 degrees (.01 * 360 / 2π) ≈ 26.5 μs (at 60 Hz)

Back up applications Power system stability Two ended fault location algorithm System diagnostics Distributed Busbar protection Load shedding Wide area frequency monitoring

Power Swing Detection Protections settings done with known max and/or min operating conditions of power system events Actual operation of power system events may not be optimal for the setting of the protection PMU provides Phasors in real time Better decision can be made on load shedding and system stability Real time Phasor value helps to fine tune State estimation

PMU : Power Swing Calculate the angle difference due to disturbance Zs 21 θ Calculate the angle difference due to disturbance Apply equal area criteria Make stability decision Angle between will vary due to disturbance Algorithm determines if diverging or settling Blocking or tripping decision to be made

Distance to Fault Single ended fault location algorithm inaccuracy Fault resistance, load flow & non homogenous system PMU enables double ended fault location PMU data from both end of the line provides very accurate fault location Reclose decision can be made for mixed overhead and cable transmission line Improved line patrolling :Better productivity & Reliability Fault location algorithm is based on positive sequence system parameters

CFE Network

Automatic Generation Shedding CFE implemented AGSS scheme CFE has generation in southeast part of the country while the large load is in the center If the angle between generation & load bus exceeds certain value, generation can be tripped Loss of 400kV transmission capacity can cause system out of step condition One line out of service : 70 Phase shift Both line out of service : 140 Phase shift CFE chose 100 to be setting for load shedding

CFE Network Ʃ + - Remote Phasor Local Phasor Threshold Trip Selected PU Cyc Trip Selected Generators

Europe System Disturbance: November 4, 2006

Grid Islanding 10 GW surplus 8.9 GW deficit 51.4 Hz 49 Hz

Resynchronisation A number of uncoordinated unsuccessful attempts made without knowledge of the overall UCTE situation Full resynchronisation after 38 minutes Source: UCTE

UCTE root cause analysis Main points: (N-1) security rule, inadequate inter-TSO coordination Lack of situational awareness Other factors (wind farms, lack of coordination)

Improvements since 2006: Situational awareness Web-based visibility of cross-border flows in Europe, RAAS – real-time awareness and alarming system Coordinated (N-1) security analysis All national files are merged into one common CE load flow file. each TSO downloads the complete system and perform complete (n-1) calculation.

PMU Testing Concepts Goal: under various conditions, make sure that the reported each PMU data message matches the expected values for each Phasor Vector, Frequency Deviation and ROCOF. Frequency Deviation and ROCOF are just numbers; tolerance is expressed as an absolute deviation from expected. Rather than express separate tolerances for phasor magnitude and angle, TVE% is introduced.

PMU Testing Standard Defined in IEEE C37.118.1 Specifies quantities to vary, ranges to vary over, and required accuracies under different conditions. Includes steady state tests, dynamic tests, and transient tests

IEEE C37.118.1 Requirements Steady state tests Dynamic tests Frequency Voltage Current Phase (discrete or continuous) Harmonic Distortion Out of band interference Dynamic tests Phase and Amplitude Modulation Phase Modulation Linear Frequency Ramp Transient tests (NYI in Protection Suite) Magnitude step Phase step Continuous phase test is equivalent to a frequency test that deviates slightly from nominal Harmonic distortion and out of band interference should not effect the PMU phasor report of the fundamental signal Modulation tests should be reflected in the PMU reported phasors Tolerances for transient tests are expressed in terms of response time, delay time, max overshoot/undershoot

Setting up a test - Hardware (PC, F6150 and PMU each have IP addresses) Protection Suite  F6150 : Waveform definitions, start time Protection Suite  PMU : Request config, start transmission F6150  PMU : Generated waveforms PMU Protection Suite : Config response, phasor data stream Connect F6150 source outputs to PMU inputs (3V + 3I) PMU may need to be configured to allow connection from PC (e.g. SEL)

Summary Synchrophasors can be put as following in power system protection and control. SCADA Wide Area PMU’s Protection Local Area Back up Protection Main Protection Local Point msec minute Time sec

Summary PMUs and WAMS enable a new dimension of monitoring power grid operation. Synchrophasors solve the problem of time incoherency required for wide-area power system control. situational awareness and alarming system will help to avoid unwanted disturbance