WPCA – AMEREN ESP SEMINAR

1 wpca AMEREN ESP SEMINARU nderstanding ESP Controls 2004, General Electric CompanyBy John KnapikGE Proprietary22 CollectionEfficiency(Percent) vs. Specific Corona PowerKNOW WHERE YOUR ESP RUNS ON THE CURVEC orona Power Watts/1000 ACFMGE Proprietary33 AVC Cabinet, CLR & T/R SetGE Proprietary44 Typical SCR-CLR Electrical SystemFiringCircuitMicroprocessor(s)Cont rolModuleCurrent LimitingReactor (CLR)Transformer/Rectifier(T/R) SetSCR StackAmASignalResistorSecondaryCurrentMa sterPrecipitatorFieldSecondaryVoltageMet erKV++-PrimaryCurrent MeterAutomaticVoltage ControlPrimary VoltageMeterVCTL - 1L - 2mAGE Proprietary55 Just Remember, the Primary of a T-R Set is Rated in Units of RMS, the Secondary is in Average 400 V AC RMS 120 A AC RMS 45 KV DC Average 750 mA DC AverageTherefore use an RMS Reading Meter to Calibrate the Primary MetersGE Proprietary66 Iron Vane MovementRMSD ArsonvalAverageNote! How Do You Tell The Difference?The Meter Scale Distance is not the Same on the RMS Proprietary77 Primary Current MeterFiringCircuitMicroprocessor(s)Contr olModuleCurrent LimitingReactor (CLR)Transformer/Rectifier(T/R) SetSCR StackAmASignalResistorSecondaryCurrentMa sterPrecipitatorFieldSecondaryVoltageMet erKV++-PrimaryCurrent MeterAutomaticVoltage ControlPrimary VoltageMeterVCTL - 1L - 2mAGE Proprietary88 Finding the Primary Current WaveformGE Proprietary99 Primary Current A Chopped Sine WavePrimary Current Waveform - Positive and Negative Half-Cycles = SCR 1 and SCR 2GE Proprietary1111 Secondary Current MeterFiringCircuitMicroprocessor(s)Contr olModuleCurrent LimitingReactor (CLR)Transformer/Rectifier(T/R)

2 SetSCR StackAmASignalResistorSecondaryCurrentMa sterPrecipitatorFieldSecondaryVoltageMet erKV++-PrimaryCurrent MeterAutomaticVoltage ControlPrimary VoltageMeterVCTL - 1L - 2mAGE Proprietary1212 Finding the mA SignalGE Proprietary1313 Secondary Current Pulsating DCGE Proprietary1414 Typical Primary and Secondary CurrentGE Proprietary1515 Secondary Voltage MeterFiringCircuitMicroprocessor(s)Contr olModuleCurrent LimitingReactor (CLR)Transformer/Rectifier(T/R) SetSCR StackAmASignalResistorSecondaryCurrentMa sterPrecipitatorFieldSecondaryVoltageMet erKV++-PrimaryCurrent MeterAutomaticVoltage ControlPrimary VoltageMeterVCTL - 1L - 2mAGE Proprietary1616 Current Limit - mA & KVGE Proprietary1717 Secondary Voltage Waveforms True NegativeKVminKVpeakmAGE Proprietary1818 Next The Automatic Voltage ControlFiringCircuitMicroprocessor(s)Con trolModuleCurrent LimitingReactor (CLR)Transformer/Rectifier(T/R) SetSCR StackAmASignalResistorSecondaryCurrentMa sterPrecipitatorFieldSecondaryVoltageMet erKV++-PrimaryCurrent MeterAutomaticVoltage ControlPrimary VoltageMeterVCTL - 1L - 2mAThe AVCAVCis the BRAINSBRAINSof the ESPGE Proprietary2020 Older Analog AVCGE Proprietary2121 Microprocessor Based AVCGE Proprietary2222 Control the amount of sparking in the ESP.

3 If a T/R set is not sparking, then its AVC should be pushing that T/R set to one of its pre-set, healthy limits (volts, amps, KV, ma, or firing angle). I ll explain what is meant by healthy in a minuteThe AVC has 2 Jobs to ExecuteThe AVC has 2 Jobs to how does the AVC know what s happening in the ESP?GE Proprietary2424 The mA signal is its eyes!Positive & Negative Ions =Charged Particles =Free Electrons =+eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee+++++e eeeeeeeeeeeeeeeGroundReturnLegTransforme r Rectifier SetPlate(+)ElectrodeKVKV Meter(PrecipitatorVoltage)mA Meter(PrecipitatorCurrent)mAeGE Proprietary2525 AVC Cabinet, CLR & T/R SetGE Proprietary2626 AVC Spark ResponseSETBACKQUENCHFAST RAMPSPARK RATESPARKGE Proprietary2727 Good Initial Settings for an = 1 Full Ramp = 5 or 6 Half = 15 to 20% Rate = 30 SPMGE Proprietary2828 Proper AVC Response to SparkingGE Proprietary2929 Spark Response - Secondary Current WaveformGE Proprietary3030 Spark Response - Secondary Current and Voltage WaveformsGE Proprietary3131 Typical Spark Response - mA & KVGE Proprietary3232 Further Control A Search Ramp RateNew Spark Threshold or T/R LimitSearch RampSpark Threshold POW Setback Slow Ramp (determined by spark rate)

4 ER Fast Ramp Quench (Response to Spark)T I M EINTERRUPTINTERRUPTPEDESTALPEDESTALRAMPR AMPPHASE BACKPHASE BACKAUTO PRCS FLWRAUTO PRCS FLWRGE Proprietary3333 Spit Spark Response (mA)GE Proprietary3434 Spit Spark Response - Secondary Current and Voltage WaveformsExamples of AVC s at a LimitGE Proprietary3636 AVC SPARK LIMITED DOING IT S JOBGE Proprietary3737T/R Current Limited with SparkingGE Proprietary3838T-R CURRENT LIMITED WITHOUT SPARKINGGE Proprietary3939T-R VOLTAGE LIMITED WITH SPARKINGGE Proprietary4040 What is meant by Healthy Limits? Primary or Secondary Limit is not healthy when accompanied by a Primary Voltage level < 90 VAC or a Secondary level < 12KV. It usually indicates a short circuit. Secondary Voltage Limit is not healthy when there is very little Secondary Current. It usually indicates an open circuit. Neither condition is aiding in particle captureGE Proprietary4141 The T-R SetFiringCircuitMicroprocessor(s)Control ModuleCurrent LimitingReactor (CLR)Transformer/Rectifier(T/R) SetSCR StackAmASignalResistorSecondaryCurrentMa sterPrecipitatorFieldSecondaryVoltageMet erKV++-PrimaryCurrent MeterAutomaticVoltage ControlPrimary VoltageMeterVCTL - 1L - 2mAGE Proprietary4242 Transformer Rectifier (T/R) SetGE Proprietary4343 Inside T/R TankGE Proprietary4444 High Voltage TransformerGE Proprietary4545 Diode StackGE Proprietary4646T/R Set -Low Voltage Junction BoxGE Proprietary4747 Low Voltage Junction BoxGE Proprietary4848T/R NameplateGE Proprietary4949 The KV MeterFiringCircuitMicroprocessor(s)Contr olModuleCurrent LimitingReactor (CLR)Transformer/Rectifier(T/R)

5 SetSCR StackAmASignalResistorSecondaryCurrentMa sterPrecipitatorFieldSecondaryVoltageMet erKV++-PrimaryCurrent MeterAutomaticVoltage ControlPrimary VoltageMeterVCTL - 1L - 2mAGE Proprietary5050 Voltage DividerGE Proprietary5151 SCR SFiringCircuitMicroprocessor(s)ControlMo duleCurrent LimitingReactor (CLR)Transformer/Rectifier(T/R) SetSCR StackAmASignalResistorSecondaryCurrentMa sterPrecipitatorFieldSecondaryVoltageMet erKV++-PrimaryCurrent MeterAutomaticVoltage ControlPrimary VoltageMeterVCTL - 1L - 2mAGE Proprietary5252 SCRGE Proprietary5353+-TimeSCRF iringAngle(90 )PowerOnConductionAngle(90 )Zero Crossings90 0 180 270 360 millisecondsTypical Sine WaveGE Proprietary5454 SCR: Low Voltage to T-R SetFiring Angle 140 Conduction angle 40 GE Proprietary5555 SCR: High Power to T-R SetFiring Angle 40 Conduction angle 140 400GE Proprietary5656 The CLRF iringCircuitMicroprocessor(s)ControlModu leCurrent LimitingReactor (CLR)Transformer/Rectifier(T/R) SetSCR StackAmASignalResistorSecondaryCurrentMa sterPrecipitatorFieldSecondaryVoltageMet erKV++-PrimaryCurrent MeterAutomaticVoltage ControlPrimary VoltageMeterVCTL - 1L - 2mAGE Proprietary5757 Current Limiting Reactor (CLR)GE Proprietary5858 Current Limiting ReactorGE Proprietary5959 Current Limiting Reactor at T-R SetGE Proprietary606090 90 SCR s are why CLR s are Needed The diagram would represent the waveform with the SCRs turning on at 90.

6 If this waveform were applied to the T/R set, very inefficient operation would occur. Output power from the T/R set would be greatly Proprietary6161To increase the efficiency of the T/R set, a device called a CLR (current limiting reactor) is used. A CLR is an inductor. Recall that the property of an inductor is to oppose a change in current. Because of this property, the shape of the current waveform is changed and it starts looking more like a sine Basics: CLRGE Proprietary6262 CLR Function Limit short circuit current Shape T/R secondary wave to be more sinusoidal Provide proper form factor Protect SCRs and T/R diodes from steep current rise Increase precipitator voltage and current Not to be confused with air core reactorGE Proprietary6363 CLR Waveform Changes with ImpedanceGE Proprietary6464 Proper CLR Sizes for Common T/R SetsAll T/R primaries are rated at 400 VPRI Current Sec. Current Minimum(Amps)(mA) (mH)40 TroubleshootingGE EnergyGE Proprietary6666TR Nameplate Values(For this exercise)Primary Current160 AmpsPrimary Voltage480 VoltsSecondary Current1200 mASecondary Voltage45 kVGE Proprietary6767 First IndicationSecond IndicationShort160480120045GE Proprietary6868 Close Clearance160480120045GE Proprietary6969 Conductive Dust, Outlet Field160480120045GE Proprietary7070 Bad KV Return160480120045GE Proprietary7171 Open160480120045GE Proprietary7272 Normal Running Condition160480120045GE Proprietary7373 SCRs Not Firing160480120045 Questions?

7 Thank You.