Megger T22/13B Instruction Manual
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Megger T22/13B Instruction Manual

Megger T22/13B Instruction Manual

15 kv burn out set
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Instruction Manual
15 kV BURN OUT SET
T 22/13B
Date of release:
2003/ 25
Item number: 128311145
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Summary of Contents for Megger T22/13B

  • Page 1 Instruction Manual 15 kV BURN OUT SET T 22/13B Date of release: 2003/ 25 Item number: 128311145...
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  • Page 5 Megger have before-hand declared their consent in writing. The content of this handbook is subject to change without notice. Megger cannot be made liable for technical or printing errors or shortcomings of this handbook. Megger also disclaims all responsibility for damage resulting directly or indirectly from the delivery, supply, or use of this matter.
  • Page 6 TERMS AND CONDITIONS OF WARRANTY Megger will accept a warranty claim brought forward by a customer for a product sold by Megger under the terms stated below. Megger guarantees that at the time of delivery Megger products are free from faults in material and workmanship which would reduce their value and serviceability to a large degree.

  • Page 7: Table Of Contents

    TABLE OF CONTENTS GENERAL 1.1. Safety instructions ............... 15 1.1.1. General safety regulations ............. 17 1.1.2. General rules for working with high voltages ......20 1.1.2.1. Supplementary instructions ............ 21 1.1.2.2. Danger of recurring voltage from space charges ....21 1.1.3.
  • Page 8 2.4.2. DC voltage testing of cables with PE or VPE insulation ..56 TECHNICAL DESCRIPTION 3.1. Specifications ............... 59 3.2. Functional description ............60 OPERATING 4.1. Safety measures ..............65 4.2. Controls and displays ............67 4.3. Burning .................. 69 4.4.
  • Page 9 TABLE OF FIGURES Fig. 1-1 Dangers of search pulse location ........1-24 Fig. 1-2 Connection regulations ............1-29 Fig. 2-1 Systematics of fault location and cable testing in power cables .................. 2-35 Fig. 2-2 Reflection factor for ohmic faults and changes in cable type ..................
  • Page 10 LIST OF ABBREVIATIONS Deutsche Industrie Norm (German Industrial Standard) Energy Seperation Filter High Voltage International Electrotechnical Commision Accident prevention regulations applicable in Germany Verband Deutscher Elektrotechniker (Association of German Electrotechnical engineers) man_t22-13b_en_01-4...
  • Page 11 EC-Declaration of conformity CE Mark We, the company Hagenuk KMT Kabelmeßtechnik GmbH Röderaue D-01471 Radeburg declare in our responsibility, that the product 15 kV BURN OUT SET is in conformity with the regulations of the Council of European Community for equalization of the rule and regulation of the member states about electromagnetic compatibility.(EMC-regulation 89/336/EWG).
  • Page 12 man_t22-13b_en_01-4...
  • Page 13 CHAPTER 1 GENERAL man_t22-13b_en_01-4...
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  • Page 15: General

    GENERAL 1.1. Safety instructions All persons involved in the installation, operation, maintenance and repair of this system must have read this user manual carefully. The instrument and all additional equipment are in accordance with the current state of safety technology at the time of delivery.
  • Page 16 Regular checks must be made to ensure that the relevant safety regulations are being complied with during operation and maintenance. The instrument may only be operated by authorised persons with the appropriate skills. Only operate the system if it is in technically perfect condition.

  • Page 17: General Safety Regulations

    1.1.1. General safety regulations Current accident prevention regulations take precedence during maintenance and repair work. Mark individual components before each repair. Only use new seals and fuses when assembling fittings and instruments as a matter of principle. Screw connections must be dry (no lubrication). All maintenance and repair work must only be carried out by staff with appropriate specialist training.
  • Page 18 Fuses The patching or bridging of fuses is forbidden, as is the use of patched fuses. When replacing fuses, only use replacements with the same or a smaller rated current strength and action (slow, quick, super-quick). Fitted bolts must not be replaced with ones for fuses with a higher rated current strength.
  • Page 19 The use of adapters and plugs which fit sockets of a different voltage is not permissible. When replacing connectors, care must be taken that the terminals are connected in proper phase. Handling regulations for cable accessories Cable terminals must be secured against working loose by means of retainer washers and spring washers.

  • Page 20: General Rules For Working With High Voltages

    1.1.2. General rules for working with high voltages Working with high-voltage devices and systems demands special care. This is particularly true of mobile operation, i.e. if the accommodation in question and its equipment do not ensure safety with permanent safety devices from the outset. VDE Regulation 0104 "Installation and operation of electrical test systems"...

  • Page 21: Supplementary Instructions

    1.1.2.1. Supplementary instructions The following supplementary instructions are not taken directly from the regulations. To avoid dangerous charges, all metal parts in the vicinity of a high-voltage system must be grounded. Special care is required in the case of mobile operation in this respect. Do not disconnect while live (risk of arcs).

  • Page 22: Safety Instructions Specific To The Measuring Van

    1.1.3. Safety instructions specific to the measuring van The measuring van/mobile pallet may only be operated on earth wire circuit resistances of ≤2 W (protective and system earth). If this cannot be ensured, the measuring van/mobile pallet must be cordoned off. The earth rod should be placed as close to the measuring van/mobile pallet as possible.

  • Page 23: Dangers Of Search Pulse Location

    1.1.4. Dangers of search pulse location In the case of classic lead-covered cables with steel reinforcement, the lead cover and reinforcement acted as earths. Owing to this large-area earthing and the associated feeding of the "earth conductor" to the fault, no dangerous resistance areas could develop.

  • Page 24: Fig. 1-1 Dangers Of Search Pulse Location

    F a u l t p o i n t Station perm. Re ≤ 2 W E a r t h r o d s u r g e V o l t a g e c r a t e r P o t e n t i a l o f a t s t a t i o n e a r t h m e a s u r i n g c a r c h a s s i s...
  • Page 25 SAFETY MEASURES TO BE TAKEN: 1. The measuring van/mobile pallet must not be set up on the route of the defective cable. 2. The measuring van/mobile pallet must only be connected to earth systems with an earth wire circuit resistance of <2 W as a matter of principle.

  • Page 26: Indications Used In The Description

    1.1.5. Indications used in the description Important instructions concerning personal protection, work safety and technical safety are indicated as follows: WARNING: Warning indicates work and operating procedures which must be complied with in full to exclude the possibility of persons being put at risk.

  • Page 27: Connection Regulations

    1.1.6 Connection regulations WARNING: Establish protective earth connection in accordance with regulations before inserting mains plug! In the case of search pulse location and discharge during a cable test, discharge currents can give rise to potential differences above ground and in potential equalization lines. If the protective earth is not connected properly, the power inputs may be damaged.
  • Page 28 The system earth of the measuring van/mobile pallet should be connected to the earthed cable shielding of the test object, or if that is not directly possible, to the connecting line to the earth connection as a matter of principle. The unused leads of the test object should if possible, and must in the case of unshielded cables, be earthed directly to the system earth connection.

  • Page 29: Fig. 1-2 Connection Regulations

    P o w e r s u p p l y f o r H V c a b l e P r o t e c t i v e e a r t h m e a s u r i n g c a r E a r t h r o d m i n .

  • Page 30: General Functional Description

    1.2. General functional description The T 22/13 B 15 kV burn-out set uses the heat of an electric arc to turn the hydrocarbons of the cable insulation at a fault point into conductive carbon. The fault resistance changes to low-impedance values, allowing it to be used for pre-location using the pulse reflection method and pinpointing using the twist method and the distortion-of-minimum method.

  • Page 31: Scope Of Delivery

    1.3. Scope of delivery Basic equipment of the T 22/13 B 15 kV burn-out set. T 22/13 B 15 kV burn-out set L304 Mains lead, 4 m, 16 A 0313 Ground cable, 25², 2.5 m 0335 HV connecting cable, 2.5 m 0403 Ground terminal for cable 0406...
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  • Page 33 CHAPTER 2 GENERAL DESCRIPTION OF MEASURING PROCEDURES man_t22-13b_en_01-4...
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  • Page 35: General Description Of Measuring Procedures

    GENERAL DESCRIPTION OF MEASURING PROCEDURES M e a sure ment of insula ting re siste nce or volta ge te sting line/ g round , line/ line, a ll c omb ina tions pre - loc a ting low- resistance faults high-resistanc e faults break Re fle c tion me a sureme nt (Te le fle x)

  • Page 36: Introduction

    2.1. Introduction The most important part of cable fault location is to find the precise position of the fault. In view of costs, the fault point should be determined with a high degree of accuracy. All fault location should be started by measuring the insulation resistance or testing the voltage in all combinations, as shown in Fig.

  • Page 37: Pre-Locating

    2.2. Pre-locating Pre-locating exploits the fact that a pulse is reflected to the start of the cable at the fault point. The entire process can be observed on a viewing instrument (e.g. TELEFLEX). Measuring the length of time between the individual reflection signals gives an indication of the approximate distance from the start of the cable to the fault point.

  • Page 38: Fig. 2-2 Reflection Factor For Ohmic Faults And Changes In Cable

    In the case of cables which go straight from one station to the next, i.e. with no branches whatsoever, measuring the reflection behaviour of the cable does not present a problem. The cable start, sleeves, cable end and any faults there may be can be seen clearly (see fig.
  • Page 39 faultless c a ble VERZWG.DRW Fig. 2-3 The branched network: idealised reflectograms Influenc e of pulse width of reflec tograms c onnec ting sleeve faultless c able faultless c able na rrow tra nsmit p ulse 1st reflec tion 2nd reflec tion rec og niza b le broad transmit pulse 1st reflec tion 2nd reflec tio n not rec og niza b le,...

  • Page 40: High-Impedance Fault Location

    Re fle c tion instrum e nts Fa ult loc a tion a nd Fa ult loc a tion q ua lity a ssura nc e symmetric a l Coa xia l Power c a b le c a b les c a b les Fa ult Pulse...
  • Page 41 In the arc reflection method the energy of a charged capacitor is discharged into the faulty cable via a shock switch. Applying a high-voltage pulse to a defective cable causes a flashover at the fault point. During the flashover the fault point forms a low-impedance crossover point using the arc which occurs there.
  • Page 42 If the arc reflection method does not produce the desired success because the surge voltage is no longer large enough for reliable firing, the decay method can be used. Unlike the arc reflection method, the decay method, which is only possible in the case of chargeable cables, charges the cable directly using a suitable voltage source (HV test unit) until the flashover voltage is achieved at the fault point.
  • Page 43 T ravelling wave display Differentiated display T eleflex Defec tive c able Connec tion test unit devic e MWG _47.DRW Fig. 2-7 Principle of the decay method man_t22-13b_en_01-4...

  • Page 44: Fig. 2-8 Test Voltage In The Cable

    Develop ment of the test volta g e in the c a b le Cha rg ing t ime t o b rea kd own, d ep end ing on t he t est unit a nd t he c a b le c a p a c it y, usua lly b et ween a few 100 ms a nd a few sec ond s Develop ment of the tra velling wa ves T eleflex...

  • Page 45: Pinpointing

    2.3. Pinpointing One of the most useful procedures in pinpointing is the application of audiofrequency and its different variants. When an audiofrequency transmitter and a receiver equipped with headphones and a search coil are used, the audiofrequency current which occurs around the cable creates a magnetic field which can be measured with the search coil.

  • Page 46: Fig. 2-9 Principle Of Magnetic Field Formation Owing To Differential

    Depending on the application, a decision must be taken with regard to the audiofrequency to be used. High frequencies of approximately 10 kHz offer advantages in terms of the signal-to-noise ratio in relation to the mains frequency and in the case of inductive connection, but they are at a disadvantage when it comes to long cables owing to the large attenuation.

  • Page 47: Pinpointing In Power Cables

    2.3.1. Pinpointing in power cables When it comes to pinpointing, it is of considerable help that, in the distance method, a powerful discharge noise is produced at the fault point as a result of the flashover. This noise can be heard using a structure-borne noise device.

  • Page 48: Distance Method

    2.3.1.1. Distance method The most important part of determining high-impedance or intermittent cable faults is pinpointing. In this procedure the surge generator as already mentioned is used, albeit with pulses of shorter duration, known as pinpointing surges. Depending on the surge energy, but also on the fault type, the flashover at the fault point produces a flashover noise (bang), which triggers an acoustic ground wave.

  • Page 49: Step-Voltage Procedure

    S ma llest d ista nc e to fa ult La rg e d ista nc e to fa ult S ma llest sound p rop a g a tion La rg e sound p rop a g a tion S ta rt sig na l from the ma g netic field time time...
  • Page 50 Right above the fault point there is a high current concentration and with it an increase in the voltage drop in the ground (see fig. 2-12 and fig. 2-13). The galvanic method with clocked DC voltage is used most frequently. It supplies a clear polarization reversal at the fault point.

  • Page 51: Fig. 2-12 Pinpointing Using The Step-Voltage Method (Capacitive)

    Development of instrument deflec tion or volume Ca p a c itive Aud io- p rob e Ground freq uenc y g enera tor SHRTTKP.DRW Fig. 2-12 Pinpointing using the step-voltage method (capacitive) History of meter indication Gro und fa ult Sh ea th te stin g p rob e g e nera to r...

  • Page 52: Audiofrequency Twist Method

    2.3.2. Audiofrequency twist method If an audiofrequency transmitter is connected to the two wires of a cable and the wires are connected at the far end or bridged by a low-impedance cable fault (short circuit), what is known as a twist field is formed. The twist field refers to the magnetic field which results from the spatial arrangement of adjacent conductors with opposing currents flowing through them.

  • Page 53: Distortion-Of-Minimum Method

    DRALLSP:DRW Fig. 2-14 Twist measurement with search coil on a 2-wire cable a) Twist field when a maximum voltage is induced in the search coil b) Twist field when a minimum voltage is induced in the search coil 2.3.3. Distortion-of-minimum method When looking for faults in cables using the audiofrequency procedure, the distortion-of-minimum method is preferred in the case of wire/sheath faults if enough is known about the...
  • Page 54 In the case of a wire/sheath fault a differential field is produced by connecting an audiofrequency transmitter between cable wire and grounded cable sheath. The receiving coil must be perpendicular to the cable as it is moved along it, as then a minimum will be indicated right above the cable.

  • Page 55: Testing Medium-Voltage Cables With Dc Or Ac Voltage

    2.4. Testing medium-voltage cables with DC or AC voltage There are essentially three factors which determine the difference between DC and AC voltage testing: Control of the voltage load is capacitive in the case of AC voltage testing and resistive in the case of DC voltage testing.

  • Page 56: Dc Voltage Testing Of Cables With Pe Or Vpe Insulation

    Travelling wave loading at a voltage level well above operating voltage is not good for a cable system. This also applies in principle to cable fault location using the decay method. This is why test procedures which reveal damage points with breakdown at a comparatively low voltage level are a good idea.
  • Page 57 CHAPTER 3 TECHNICAL DESCRIPTION man_t22-13b_en_01-4...
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  • Page 59: Technical Description

    TECHNICAL DESCRIPTION 3.1. Specifications Power supply 230 V + 5% / - 10%, 50 Hz Current consumption max. 16 A Power consumed 3.5 kVA Output voltage/no load max. 15 kV Output current in short circuit: without power adjustment 300 mA with power adjustment 25 A Peak current...

  • Page 60: Functional Description

    3.2. Functional description The T 22/13 B 15 kV burn-out set is short-circuit proof and supplies constant power to the changing fault resistance over a range of currents (constant power characteristics). The burn- out voltage is infinitely variable. Output current and output voltage are displayed on instruments, each with a choice of two measuring ranges.
  • Page 61 An internal discharge device takes care of discharging the unit and the test object. The charging capacitor discharges via resistors with a time constant of 20 s. If it has to be discharged more quickly, the spark gap can be closed when switching off. Discharge will now take place via the discharge device.
  • Page 62 man_t22-13b_en_01-4...
  • Page 63 CHAPTER 4 OPERATING man_t22-13b_en_01-4...
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  • Page 65: Operating

    OPERATING 4.1. Safety measures The following safety measures must be complied with to avoid personal injury or material damage as a direct result of operation of the T22/13 B by itself or in combination with other equipment: Check the immediate area surrounding where the T 22/13B is being used for any unprotected live equipment/plant components with which you or the unit might unintentionally come into contact.
  • Page 66 Choose a site for the unit that satisfies weight and dimension requirements and provides a secure "base". Make sure that the proper functioning of other equipment/plant components is not impaired by the installation of the T22/13 B. If other equipment/plant components have to be modified to accommodate the installation and operation of the generator, make sure that such measures are reversed once the work has been...

  • Page 67: Controls And Displays

    4.2. Controls and displays Adjustment of regulating transformer Adjustment of spark gap Voltmeter 0...20 kV Switch for voltmeter measuring range 5 kV/20 kV Ammeter 0...30 A Switch for ammeter measuring range 0.3 A/30 A Switch for clocking "HV on" indicator lamp "HV on"...
  • Page 68 T 2 2_ 1 3 0 2.drw Terminal for protective ground Control socket for T 22/13 B (short-circuit plug to be inserted when the T 22/13 B is operated on its own) Mains socket Safety switch (shutdown when HV plug is removed) HV socket man_t22-13b_en_01-4...

  • Page 69: Burning

    4.3. Burning N.B.: Please note that current safety regulations regarding the use of high-voltage and heavy-current systems must be complied with before the unit is put into operation (s. also chapter 1). WARNING: The protective ground terminal (fig. a-2 [1]) of the unit must be connected to the station protective ground (frame ground) before the test object is connected.
  • Page 70 For fault burning, proceed as follows (see fig. a-1): a. Turn mains switch [11] on b. Green mains control lamp [10] comes on c. Spark gap [2] is closed (0.3 A measuring range) when the spark gap is open, the output current of the burn- out set is not displayed in the 0.3 A measuring range.
  • Page 71 ATTENTION: Premature opening of the spark gap can lead to excess voltages (doubling of voltage by travelling waves). k. Open spark gap (fig. a-1 [2]) until continuous flashovers (100 Hz rate) can be heard l. Stop burning when current (see k.) stops rising m.

  • Page 72: Pre-Locating

    4.4. Pre-locating 4.4.1. Pre-locating using the arc surge method With the T 22/13 B 15 kV burn-out unit pre-locating using the arc surge method (section 2.2.2.) is possible with a very high surge rate (also called arc burning). The high rate means that the reflectogram appears continuously on the screen of a TELEFLEX.

  • Page 73: Ground Fault Measurements

    ATTENTION: In this mode care must be taken that the spark gap must be closed as HV pulses could endanger the T 32/23 pre-locating unit. 4.4.3. Ground fault measurements Because of its built-in clocking (1 s operation/3 s pause), the T 22/13 B 15 kV burn-out unit can be used for ground fault measurements with the T 32/21 ground fault probe: a.
  • Page 74 man_t22-13b_en_01-4...
  • Page 75 CHAPTER 5 CARE, MAINTENANCE AND REPAIR man_t22-13b_en_01-4...
  • Page 76 man_t22-13b_en_01-4...

  • Page 77: Care, Maintenance And Repair

    CARE, MAINTENANCE AND REPAIR 5.1. Care and maintenance The T 22/13 B 15 kV burn-out set requires no maintenance. The housing surfaces and controls should be cleaned with a mild cleaning agent. Naphtha, acetone, lyes or similar agents must not be used under any circumstances, as they attack the housing surfaces and possible equipment failure cannot be ruled out.

  • Page 78: Troubleshooting

    5.2.2. Troubleshooting Plug right in HV socket (fig. a-2 [5])? Check that plug is firmly in socket System ground connected, or surge Allow approx. 30- to protective ground? minute cooling break Unit switches off after 5...10 minutes Allow approx. 30- when burning with 20...30 A minute cooling break Overload protection of HV...

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