Doble Solutions for Partial Discharge. Greg Topjian Solutions Manager

Transcription

1 Doble Solutions for Partial Discharge Greg Topjian Solutions Manager

2 Why do we need to conduct PD measurements PD a major cause of early failure for HV insulation.

3 Partial Discharge PD is a symptom of degradation. Once present it dominates as it s own inherent stress degradation mechanism Its an early waning signal and precursor to complete insulation failure and breakdown PD diagnostics can be used to trend changes in the level and severity of insulation degradation Early detection of PD is critical in the prevention of in catastrophic failures

4 What Does PD Depend On? Electrical field stress Environment conditions - Temp and humidity Load or current Mechanical vibration Important to have early stage of detection for PD PD diagnostics: Used to trend changes in level and severity of the degradation of equipment installation

5 Partial Discharge Causes of PD in insulation system: Voids in epoxy resins, polymers, paper Bubbles in liquids/oils Metal deposits, irregularities such as protrusions, contaminants Electrodes and insulation surfaces and interfaces Can arise through: Poor design and manufacture Damage of equipment e.g. Transport damage Poor installation processes poor workmanship General ageing or deterioration of materials

6 Why is Testing and Monitoring for PD Important?

7 Why is Testing and Monitoring for PD Important?

8 Why is Testing and Monitoring for PD Important?

9 Why Is testing and monitoring for PD Important? 9

10 Doble s 4-Phased PD Products Phase 2 PD-Smart Testing Phase 1 Survey Instrument (PDS 100 and DFA) 100) Phase 3 LDA6 Acoustic Locator (Transformers Only) Phase 4 Permanent Monitoring (Guard-Family)

11 PD Alignment with Doble Services Four phases: Services wrapped into Phase 2-4 Phase 1: Surveying Phase 2: Testing on- or off-line Phase 3: Investigative methods Phase 4: Permanent monitoring Phase 5: Doble Service Agreement (DSA)

12 PD-Smart Combine System Includes electrical and UHF capabilities combined into one unit that will test PD on: Transformers Rotating machines (RM) MV/HV cables GIS And MORE!

13 PD-Guard Monitoring System Key features: Advanced signal processing Interference suppressions Analysis software Continuously monitors your critical assets Most important: Automatic alarm system based on changes in activity rates rather than maximum values; this avoids false alarms due to one-time outliers An important part of a thorough conditionbased maintenance program

14 Activity Rate Changes Monitoring changes in activity rates rather than maximum values avoids false alarms. 14

15 PD Key Markets Testing Rotating Machines (Motors & Generators)

16 PD of Rotating Machines

17 Rotating Machines Testing/Monitoring Periodic testing with PD-Smart + Sensor + Connection Box Permanent monitoring with PD-Guard

18 System Components Permanent PD testing with PD-Smart on machines

19 System Components Permanent PD monitoring on machines Motor or Generator Bus Work A B System Components PD-Guard 3-4 PDDC-24 or PDDC-17 Calibrator Doble PD Support + Neutral Inductive Sensor Pulse Disturbance Gate PD-Guard C Fiber Optic LAN Coupling Capacitors & Installation Kits Calibrator PD Evaluation Server Analysis Software

20 IEC60270: Frequency is important! Doble Lemke uses 2nF coupler, whilst other suppliers using 80pF, 200pF coupler A coupler with a capacitance of 80F,200pF sees only the first part of the winding. Deeper Discharges / Slot Discharges will maybe not detected Coupler with 80pF, 200pF are not conform to the international standard as the measuring frequency is much higher as specified in the standard

21 PD Pulse vs. Location in RM Many generators have high frequency (HF) couplers installed with a strong high pass behavior, hampering PD measurement. HF couplers exhibit good performance for measuring PD close to it that is at the line end of the winding. They are worse than low frequency (LF) couplers for detecting PD in the middle and neutral end of the winding.

22 BC-Matching Unit (HF-Expander) PD-Measurement according to the standard of IEC60270 with a HF coupler + + High Frequency Coupler BC-Matching Unit PD-Smart

23 PD Key Markets Transformer Testing

24 Reasons for Testing and Monitoring to Avoid

25 UHF PD-Smart Testing Pulse Generator LDC-7/UHF

26 UHF PD-Guard Monitoring Doble TransformerGuard Computer(s) for Remote Control & Analysis UHF Plate Sensors (Mounted in Hatch) LAN / WAN / Internet PD Monitoring Server Software Ethernet Hub Interfaces: ActiveX Control DCOM-Interface M MODBUS Fiber optic LAN PD-Guard/UHF UHF Drain Valve Sensors

27 PD Measurement on Transformers Tank Valve Connector

28 Sensor Application Measuring Impedance PD Measuring Impedance for Bushing Tap Installation

29 Doble Acoustic PD Locator: LDA-6 For Transformers Only Multi-channel acoustic transient recorder 4 or 8 acoustical channel External triggering channel Intuitive PD location software Piezo-electric acoustic sensors & magnetic clamps

30 Comments Acoustics Acoustics are a valid technique for locating PD but it s the wrong approach for detecting PD due to low sensitivity of the AE method and the fact that PD imbedded in the winding will not produce acoustic pressure waves detectable on the tank wall. So no Acoustic Signal does not mean no PD and detection via HF-CT on the star point end will only work for strong PD

31 Comments Acoustics (Cont d) Some companies have convinced many Clients in our Region that Acoustic Measurements is detection of PD which is fundamentally wrong We obtain greater location accuracy using UHF triggering. Biggest Market for Location is probably service work

32 Acoustic PD Locator: LDA-6 1 Sensor 1 Sensor 2 Sensor 3 Sensor 4

33 Online Monitoring

34 PD Key Markets Cable Testing (on Site)

35 Terminations & Joints 1. Incorrect installation / poor workmanship 2. Manufacturing issues poor QA

36 The Problems Termination Aging Joint Weak Spot There is a wide range of possible problems in cable installations Apart from physical damage external defects in joints and terminations is the dominant cause of failure In addition some type and vintage of cables developed water treeing for various reasons but often related to outer sheath /jacket damage All of these problems may result in reduced life expectancy and premature failure of the cable

37 Cable Termination: PD-Smart/Guard PD-Smart: + For Periodic Online testing PD-Guard UHF Sensors + HFCT + Connection box For Online monitoring

38 PD-Smart Cable Termination HFCT

39 Cable Termination: PD-Smart/Guard

40 PD Key Markets Switchgear Testing (MV & GIS)

41 MV Switchgear Monitoring In MV switchgear often high humidity leading to surface tracking, material defects and incorrect assembly are responsible for PD activity

42 Gas Insulated Switchgear (GIS) On-line PD Smart -UHF LDS6-UHF Schematic diagram of the PD-UHF-Monitoring-Setup at GIS by using UHF-Spacer-Sensor or internal sensor PD sensor: spacer type frequency range: 100 MHz 1200 MHz Internal UHF sensor integrated in GIS

43 Doble s PD Product Offerings Phase 2 PD-Smart Testing Phase 1 Survey Instrument (PDS 100 and DFA) 100) Phase 3 LDA6 Acoustic Locator (Transformers Only) Phase 4 Permanent Monitoring (Guard-Family)

44 Questions? Contact: Greg Topjian Solutions Manager