Recognize long-term trends with Partial Discharge Monitoring
Partial Discharge Monitoring ("PD Monitoring") describes the measurement and recording of partial discharges over a longer period. PD Monitoring is done during normal operation conditions, this means online permanent PD measurements will be carried out. Partial discharge monitoring allows long time trending of partial discharge events, rather than only at a flash point during a periodic test. Hence, with partial discharge monitoring, a change in the insulation system of your HV equipment can be recognized in an early stage.

From time-based to condition-based asset management
Condition based maintenance as well as asset management strategies, realized via partial discharge monitoring, are particulary relevant for power apparatus that are located at critical points of the power generation and transmission grid. Partial discharge monitoring will increase the availability as well as the operating safety of your HV equipment and allows the timely planning of outages.

Our Measuring Devices - Our Solution - Your Benefit
Our product range includes innovative digital partial discharge monitoring systems, that can be easily integrated into utility control and SCADA systems. Furthermore, for PD monitoring permanent sensors have to be installed at the HV equipment, both standard as well as customized sensors are offered.

Due to the permanent installation of PD monitoring systems on-site, many filter and noise suppression features are implemented. The partial discharge monitoring systems are scaleable and remote controlled. Highly sophisticated software simplifies the evaluation of the data for the end-user. Moreover, an intelligent database allows the meaningful assessment and analysis of relevant data. User defined alarm conditions, combined with a plenty of analysis tools, facilitate decisions for appropriate electronic counter measures.

PD-Guard/UHF

For the implementation of permant UHF partial discharge measurements, the PD monitoring system PD-GUARD/UHF is used. The PD-GUARD/UHF is especially designed for continous PD monitoring on gas-insulated switchgears (GIS) and cable systems. The decoupling of the partial discharges will be done in the UHF frequency range.

PD-Guard

The PD monitoring system PD GUARD is especially developed for continuous partial discharge monitoring of high voltage equipment, like generators, motors and power transformers in the conventional frequency range.

Power transformers are subject to many kinds of physical damage that can be nearly impossible to detect – until the transformer fails!

System faults, short circuits, aging or even handling during transportation may compromise the mechanical structure of a transformer. Because these problems are difficult to detect, they usually go unnoticed and worsen over time, leading to loss of performance and possibly failure.

Until recently, your options for dealing with these critical problems were limited. You could ignore them and hope for the best. Or, if you suspected damage, you could detank the transformer to make a costly and time consuming visual inspection. And even that might not reveal the damage.

At Doble Engineering, we have built on our experience with transformers to create the M4000 Series and M5000 Series.

The M4000 Series uses patented state-of-the-art technology to accurately evaluate the condition of substation high voltage power apparatus, even under conditions of high electrostatic and electromagnetic interference. For more information, go to:

• M4000

Doble’s M5000 Series uses Sweep Frequency Response Analysis (SFRA) for detecting mechanical failure or movement of windings due to short circuits, mechanical stresses or transportation. Use it to ensure transformer performance, reduce maintenance cost, and increase the service life of transformers.

For more information on Doble's SFRA Diagnostic instruments, go to one of the following pages:

• M5300
• M5200

Sweep Frequency Response Analysis (SFRA) Overview

Sweep Frequency Response: A major advance in transformer condition analysis.

The standard definition of frequency response analysis (FRA) is the ratio of a steady sinusoidal output from a test object subject to a steady sinusoidal input. Sweeping through the frequency range of interest gives rise to the S in SFRA to distinguish it from impulse methods where the response is estimated rather than measured. Sweep Frequency Response Analysis is a proven technique for making accurate and repeatable measurements. As compared to the “Impulse” technique, the SFRA technique is the preferred method for making frequency domain measurements.

How SFRA works in Doble's M-Series Test Equipment:

Doble's M-Series equipment sends an excitation signal into the transformer and measures the returning signals. By comparing this response to baseline and other results (such as from similar units), you can identify deviations and confirm internal mechanical problems.

The SFRA Technique

Covers the full dynamic range and maintains the same energy level for each frequency, providing results that are consistent and accurate. High signal-to-noise ratio across the entire 20 Hz to 2 MHz frequency range ensures valid measurements.

SFRA Resource Center

The Doble SFRA Resource Center is a collection of documents which cover many aspects of Transformer Frequency Response Analysis (FRA) using Doble's M5100 Sweep FRA (SFRA) test set.

To learn more about the basics of SFRA, click here to read an article on the topic

Doble's M5000 Series

Doble’s M5000 Series uses Sweep Frequency Response Analysis (SFRA) for detecting mechanical failure or movement of windings due to short circuits, mechanical stresses or transportation. Use it to ensure transformer performance, reduce maintenance cost, and increase the service life of transformers.

For more information on Doble's SFRA Diagnostic instruments, go to one of the following pages:

• M5200
• M5300

Surge Arresters Monitoring

Doble's TransiNor office created the LCM II System for managing your surge arrester monitoring needs. This portable, cost-effective system uses Windows© LCM II Software and created a unique identification of each surge arrester for easy data management. LCM II can be used for continuous monitoring of one or more arresters to investigate details in leakage current changes versus the length of time in which they occur.

LCM II

LCM II is the complete system for condition monitoring of your Metal Oxide Surge Arresters.

«No interruption of service operation»

What is the Partial Discharge Phenomena?
Partial Discharges (PD) are evidences of a degrading insulation capacity, which will lead to cost-intensive repairs and can predictively lead to an electrical breakdown of the HV apparatus.

Partial Discharges are mainly caused by natural circumstances or by accelerated aging of the HV insulation. But also manufacturing or installation failures can lead to harmful partial discharges. Therefore, the goal of partial discharge measurements is to detect the partial discharges in an early stage and to evaluate them in a proper way.

Thus, periodic (as well as permanent) partial discharge measurements have become one of the main criteria in assessing the quality and condition of HV equipement such as transformers, generators, switchgears and cable systems.

Our Measuring Devices - Our Solution - Your Benefit
Based on many years of research and development, the Doble-Lemke Group offers various state-of-the-art partial discharge measuring devices and systems.

Our highly sophisticated measuring instruments and systems, either on digital or analogue basis, allow partial discharge measurements according to national and international standards such as DIN EN IEC 60270, DIN EN IEC 62478 (pending), DIN VDE 0434, various IEEE standards as well as other standards of the High Voltage Test and Measurement Technology.

Avoid costly repair work and and long-term breakdown of your HV apparatus
- Rely on partial discharge measurements for condition assessment of your transformer, generator, cable system or switchgear!

PDS-100

The Partial Discharge Surveyor PDS100 provides complete substation PD survey capabilites. By simply walking around the HV apparatus, sources of partial discharges and external intereference can be detected and identified. Routine RFI surveying will assist in locating partial discharge activity while the apparatus is still in service.

PD-Smart

Our digital, highly advanced partial discharge measuring and diagnostic device PD SMART is characterized by its unique compactness and its precise measurements.

PD-Smart Measuring Sensor

High-precision, modular acquisition and analysis system for measuring current and key characteristics of electrical equipment, including dissipation factor and capacitance.

LDS-6&LDS-6/UHF

For over 10 years, the digital and portable PD measuring and diagnosis device LDS-6 accompany thousands of users around the world. With the help of the various plug-in's, the LDS-6 allows also narrow-band, RIV and UHF partial discharge measurements, besides conventional PD measurements. Read more LDS-6... Read more LDS-6/UHF...

LDP-5

The portable Differential LEMKE PROBE LDP-5 detects and locates dangerous partial discharges in HV equipment. Due to the light-weight construction, the Lemke probe LDP-5 can be used for both on-site inspections and measurements in the laboratory.

LDA-6

The LDA-6 is used for acoustic localization of partial discharges inside power transformers. The acoustic, multi-channel detection of partial discharges can also be combined with electrical partial discharge measurements.

LDA-5/S

The PD detector LDA-5/S is used for detection of the ultrasonic sound signal of PD events at a resonance frequency of 40 kHz. Depending on the type of ultrasound receiver, either partial discharges in air (corona) or in HV equipment can be recognized, as for instance in cable systems, power transformers and switchgears (incl. GIS).

DFA100 - Dielectric Fault Analyzer

The DFA100, Dielectric Fault Analyzer, is a handheld, battery-powered instrument for monitoring non-intrusive, in-service acoustic signals produced by partial discharge and loose components DFA100 for Gas Insulated Substations The DFA100 for GIS is a hand-held instrument for acoustic diagnosis of Gas Insulated Substations. It is a battery-powered instrument for detection and location of defects in the insulation of GIS systems. The DFA100 includes an acoustic emission (AE) sensor to detect acoustic signals from a range of defects such as bouncing particles, protrusions and mechanical loose parts. DFA100 is a further development of its predecessor AIA, a widely known and accepted tool for diagnosis of GIS.

DFA100 for Cable Applications

The DFA100, a hand-held instrument also for diagnosis of cable accessories. It is a battery powered instrument for detection and location of internal Partial Discharge (PD) in the insulation of cable accessories. The DFA100 includes an acoustic emission (AE) sensor and an acoustic wave guide consisting of insulated hot sticks.

MachineGuard PD Monitoring System

Doble offers a complete solution for monitoring Partial Discharge on rotating machines. The system includes the Doble PD-Guard, couplers, calibrators, interference rejection sensors, and all necessary connectors. Of course, the system comes with Doble’s world class support.
► Click Here for the MachineGuard Brochure

 

Why is MachineGuard simply the most advanced PD monitoring system? Click here to check out the spec!

 

 

FailSafe LF & Capacitive Couplers

 

Doble offers a variety of capacitive couplers that allow for decoupling of PD signals from various electrical sources. Featured is the FailSafe LF Coupler. This coupler allows for continuous online monitoring of rotating machines at lower frequencies than traditional HF couplers. Lower frequencies allow for the whole stator to be monitored, not just the first few coils. In addition, the unit does not compromise the reliability of the system by incorporating a fused element that safely removes the coupler in the event of a failure.
► Click Here for the FailSafe LF Couple Brochure

 

 

 

TransformerGuard PD Monitoring System

TransformerGuard is a solution for monitoring PD activity in transformers. It is equipped with a PD-Guard/UHF that allows for the connection of various UHF sensors that can be either mounted through tank hatches or inserted through an oil drain valve. UHF technology allows for detection of PD activity deep within transformer windings without attenuation. Doble’s experts will assist you in analysis.
► Click Here for the TransformerGuard Brochure

TerminationGuard PD Monitoring System

TerminationGuard is a condition based monitoring system for assessing the condition by cable terminations in the field. Once installed in the field, the most likely place for a cable to fail is either at splices or terminations. TerminationGuard targets the terminations and can reliably assess their condition by using the latest in UHF PD based technology. By monitoring the in-service partial discharge, the insulation performance can be monitored over time and corrective action can be taken before a failure occurs.
► Click Here for the TerminationGuard Brochure

Doble has created the DOMINO Moisture-in-Oil sensor to manage the state of your bushings/CTs, transformers and circuit breakers. The DOMINO Moisture-in-Oil sensor is an accurate, simple, robust and versatile instrument, measuring just that: moisture in oil in terms of ppm and relative saturation plus the added benefit of temperature. It is a sensor that provides for the continuous reliable measurement of the water content of electrical insulating liquids and other types of oils.

The Doble Laboratory can provide answers and solutions to your problems based upon quality data from a wide scope of testing capabilities and a rich experience in apparatus diagnostics. We can help you develop the most cost-effective testing program for condition assessment or help identify and solve apparatus problems. All test reports include an analysis of the data and recommendations for remedial action if warranted.

DOMINO

Doble Engineering developed one of the first analytical techniques for the measurement of dissolved water in oil and also developed probably the first on-line moisture monitors, the DOMINO.

DOBLE LABORATORY

The Doble Laboratory is fully equipped to perform a wide variety of tests on insulating materials, with more than fifty tests offered on a routine basis.

CONTINOUS ONLINE DIAGNOSTICS

Doble has created a variety of online devices to manage the state of your bushings/CTs, transformers, circuit breakers, and other apparatus.

Doble's Insulation Analysis equipment is the world's most advanced test system for power apparatus. The M4000 is the leading system for evaluating the condition of high voltage power apparatus. It sets the standard for accuracy, reliable test results, and intelligent diagnostics for customers worldwide.

The M4100, together with the DTA Expert System Software, represent the new generation of smart, automated test equipment used to determine the condition of high voltage substation apparatus.

M4000

This multi-purpose instrument can perform a variety of tests and diagnostics on a wide range of power apparatus, ensuring that your testing program is a success.

DTA Software

The DTA (Doble Test Assistant®) software module takes users through the entire test process step by step. DTA includes expert system software that analyzes results according to 3,700 rules and guides the user to the appropriate maintenance decision—providing answers, not just data.

M2H MCM

The new M2H - MCM (M-series Control & Measurement) Insulation Analyzer brings automatic Power Factor measurement techniques to M2H users in an easy to use instrument package. The M2H - MCM provides a graphical user interface, automated measurements, and data management to M2H users, producing stable test results and fast test times

Doble has created a variety of online devices to manage the state of your bushings/CTs, transformers, circuit breakers, and other apparatus.

DOMINO

Obtaining accurate moisture and temperature data is necessary to determine the condition of electrical apparatus or its insulating liquid. However, the data by itself may not always be sufficient to identify potential problems, especially in transformer systems. Doble Engineering developed one of the first analytical techniques for measuring dissolved water in oil and the first online moisture monitor: DOMINO.

Insulator Pollution Monitor (IPM)

The IPM is designed to perform­ continuous online m­onitoring of external pollution effects on high-voltage insulators and other insulator housings, such as surge arresters and bushings.

Intelligent Diagnostic Devices

Doble created Intelligent Diagnostic Devices (IDDs), a family of continuous online diagnostic devices for power system apparatus intended to detect incipient problems with bushings/CTs, transformers, and circuit breakers. Now you can safely manage progressive problems and efficiently schedule corrective action. There are three types of IDD instruments: Moisture, Bushings, and Dissolved Gas Analysis.

LCM II

TransiNor created the LCM II to monitor the condition of high-voltage Metal Oxide Surge Arresters (MOSAs) in service. This complete system for condition monitoring measures the resistive component of the MOSA leakage current. Increased resistive leakage current indicates a higher risk of MOSA breakdown.

Circuit Breaker Diagnostics

Doble's circuit breaker diagnostic products provide you a method for testing everything from simple circuit breakers to complex ones, using a single, field-portable, rugged instrument and Windows-based software. The modular design allows you to acquire a circuit-breaker test system matched to today's specific testing applications and to upgrade in the field to test different or more complex apparatus.

Doble offers the following circuit breaker diagnostic instruments and software: