YH10W-15 LIGHTING ARRESTER 10kA


INSTALLATION INSTRUCTION

1.     GENERAL
Metal oxide surge arrester (MOA) is recognized as the upto-date overvoltage protector which ,due to the inherent superior nonlinear V-A characteristics and steep-wave response of metal oxide varistors ,can suppress overvoltages to a relative low level ,thus providing a reliable protection for insulation of electrical apparatus.
The basic technical parameters are complied with the technical specification of Chinese Standard GB11032-2000 which is exactly equivalent to IEC60099-4
2.     THCHNICAL DATA
ZINC OXIDE PROTECTIVE CHARACTERISTICS (10kA NORMAL DUTY POLYMER)  
3.     APPLICATION CONDITION
3.1 Normal Service condition
Surge arresters which conform to this standard shall be suitable for normal operation under the following normal service conditions:
   Ambient air temperature within the range of -40 ºC to +40 ºC.
   Solar radiation :The effects of maximum solar radiation (1.1kW/m ²)have been taken into account by preheating the test specimen in the type tests. If there are other heat sources near the arrester, the application of the arrester shall be subject to an agreement between the manufacturer and the purchaser.
   Altitude is not exceeding 1000m.
   Frequency of the A.C power supply is not less than 48Hz but not more than 62HZ.
   Power frequency voltage applied continuously between the terminals of the arrester is not exceeding its continuous operating voltage.
   Mechanical conditions ;no strong vibration.
   Pollution conditions: no requirement at this time.
3.2 Abnormal Service Conditions
Surge arresters subject to other than normal application or service conditions may require special consideration in design, manufacture or application. The use of this standard in case of abnormal service conditions is subject to agreement between the manufacturer and the purchaser.
5. INSTALLATION AND PRECAUTION
5.1 The surge arrester is fixed to the supporting structure by fitting-bracket, and connecting its top terminal to H V wire of electrical apparatus ,which is protected ,with 8-16 mm² copper wire, connecting its chassis cover to the terminal of operation counter, connecting the other terminal of operation counter to the ground wire, or connecting its chassis cover to the ground directly.
5.2 The surge arrester should be lain close to the electrical apparatus, which is protected ,for protective effects. When the transformer is protected ,the distance between the arrester and on the low voltage side of a distribution transformer in case any damage to the insulation caused by forward-backward over voltage
5.3 After bring the surge arrester into operating ,should be do preventive test every two years, measuring the leakage current of arrester at DA 1mA.
5.4 Please don't break open the surge arresters.
5.5 This product is warranted against defects in workmanship and materials .If any failure ,resulting from a defect in either workmanship or material, is occurred under the normal using within one years form the date of purchase ,we shall replace it in free of charge.
         
 
 
 
 
88Kv
 
 
 
   
  33kV LIGHTNING ARRESTER
Quantity Required = 3 units
1     SCOPE
The specification covers the design, manufacture, laboratory testing before dispatch, supply and delivery of static class, heavy rating, gapless, metal (zinc) oxide lighting arrestors. The arresters shall be supplied complete with clamps, complete fitting and accessories for installation on outdoor type 33kV and 11kV switchgear, distribution lines and transformers.
 
Distribution electrical equipment e.g. transformers that are connected to overhead, open wire primary feeders are often subjected to severe lightning disturbances. To minimize insulation breakdown and equipment failure, lightning arresters are general applied to protect the equipment.
The Supplier shall state name, place and country of manufacture. The Supplier shall state whether or not the lightning arresters are produced under license, in which case the licence holders' name shall be stated.
Tenderers shall include a complete statement of compliance with this specification.  For every clause in this specification the Tenderer shall state compliance or non-compliance and shall elaborate where appropriate.
Tenderers shall use the words "comply", "do not comply" with this specification or in the clauses of an informative nature, "noted".  Where the words "do not comply" are used the Tenderer shall state whether modifications could be made and whether modifications would be undertaken.  The cost implications of such modifications must be indicated in the statement of compliance as well as the pricing schedules.
           
 
 
2.    DETERMINATION OF RESPONSIVENESS
Prior to the detailed evaluation of Tenders, ZETDC will determine whether each Tender is substantially responsive to the requirements of the Tender Document.
For the purpose of this clause, a substantially responsive Tender is one which will conform to all the terms, conditions and specifications of the Tender Document without material deviations or reservations. A material deviation or reservation is one which affects in a substantial way the price, scope, quality, completion, timing or administration of the works undertaken by the Tenderer under the Contract, or which limits in a substantial way, inconsistent with the Tender Document, the Zimbabwe Electricity Transmission and Distribution Company's rights or the Tenderer's obligations under the Contract and the rectification of which would affect unfairly the competitive position of other Tenders who have presented substantially responsive Tenders at reasonable price.
 
 
A Tender determined to be substantially non-responsive will be rejected by the Authority and may not subsequently be made responsive by the Tenderer by correction of the non-conformity.
The Zimbabwe Electricity Transmission & Distribution Company may accept any non-material deviation or reservation provided that the acceptance thereof does not prejudice or affect the relative ranking order of any tender in the evaluation of tenders.
 
 
3.    PARTICULARS OF THE ELECTRICAL SYSTEM
 Unless otherwise specified in the Schedule of Requirements, it must be assumed that the electrical system in which the lightning arresters will be used in is;
a)     Three phase overhead-line construction and underground system. The maximum earth fault factor on the network is 1.5.
 
b)    Operated at 50 Hz, with approximately sinusoidal wave form.
 
c)     The highest system voltage does not normally exceed the nominal system voltage by more than 10%.  The nominal system voltage is 33 kV.
 
d)    The system frequency variation does not exceed plus or minus 2.5% from 50 Hz.
 
       e)  Maximum Short circuit current of 15kA for 33kV network.
 
Designs should allow for these variations.
 
 
4.    PARTICULARS OF THE ENVIRONMENT
 Lightning arresters will operate within the tropics and will be subjected to sudden ambient air temperature changes of the order of 10 ° C per hour, occurring at the onset of rain, but the barometric pressure at any given place does not vary by more than approximately 10mm Mercury.   Frequent and severe lightning storms occur during summer months, with isoceraunic levels varying between 50 and 100 thunderstorm days per annum.
The Lightning arresters shall be capable of operating under the following environmental conditions.
a)       Ambient temperatures:
             (i)    Maximum:             40 °C
              (ii)    Minimum:             minus 10 °C
                   (iii)   Maximum daily average: 35 °C
 
 
 
b)     Altitude:
Maximum altitude of 1 500 metres above sea level.  The design shall allow for reduced
Cooling effect due to high altitude. 
       c)    Humidity:
Humidity of 13mg per cubic metre absolute and 65% relative before storms with vapour pressure of 17mmHg.
       d)    Lightning:
Frequent and severe lightning storms occur during summer months, with isoceraunic levels varying between 50 and 100 thunderstorm days per annum.
e)             Dust:
Particular attention should be paid in the design of all equipment to ensure that there is no damage to working parts or insulation through the ingress of dust, insects, vermin which are prevalent for long periods in the year.
It is the supplier's responsibility to make himself familiar with any other climatic and physical conditions pertaining in Zimbabwe and to supply lightning arresters which meet all such conditions.
 
 
5.    LANGUAGE, UNITS AND STANDARDS
 All tenders, correspondence, description upon drawings, illustrations or instructions shall be in unambiguous English Language. SI units of measurements shall be used throughout.
Except where modified by ZETDC's specifications, IEC recommendations (IEC 60099) or BS EN 60099-5:1997 shall apply throughout. In the case of conflict between the above stated standards and this specification, the ruling of this specification shall prevail.
 
 
6.         TECHNICAL SCHEDULES
The Technical Schedules shall be filled in and completed by the Bidder, and submitted with the Bid. All data entered in the Schedules of Technical Guarantees are guaranteed values by the Bidder and cannot be departed from whatsoever. All data entered in the Schedules of Informative Data are also guaranteed values by the Bidder.  These data may only be altered following the Engineer's written consent.
 
 
 
 
 
 
 
 
 
7.0           DESIGN & CONSTRUCTION
             
The metal oxide gap less Lightning Arrestor without any series or shunt gap shall be suitable for protection for 33kV side of Distribution Transformers. The lightning arrestor shall draw negligible current as operating voltage and at the same time offer least resistance during the flow or lightning current. The lightning arrestor shall consist of non-linear resistor elements placed in series and housed in electrical grade silicon polymeric housing of specified creepage distance. The assembly shall be hermetically sealed with suitable rubber gaskets with effective sealing system arrangement to prevent ingress of moisture. The lightning arrestor shall not operate under power frequency and temporary over voltage conditions but under lighting conditions, the lightning arrestor shall change over to the conducting mode.
Lightning arrestors shall have a suitable pressure relief system to avoid damage to the silicon polymeric housing and providing path for flow of rated fault currents in the event of arrestor failure.
The reference current of the arrestor shall be high enough to eliminate the influence of grading and stray capacitance on the measured reference voltage.
The Lighting Arrestor shall be thermally stable and the supplier shall furnish a copy of thermal stability test along with the bid.
The arrestor shall be capable of handling terminal energy for high lightning, external pollution and transient over voltage and have low losses at operating voltages.
The lightning arrestor shall be provided with line and earth terminals of suitable size. The line side terminal shall be suitable for a conductor equivalent to ACSR weasel / rabbit conductor. Lightning counter, leakage detector is not required for the lightning arrestors.
 
7.1 Arrestor Housing
The arrestor housing shall be made up of silicon polymeric housing and shall be homogenous, free from laminations, cavities and other flaws of imperfections that might affect the mechanical and dielectric quality. The housing shall be of uniform brown colour, free from blisters, burrs and other similar defects. Arrestors shall be complete with insulating bases fasteners for stacking units.
The housing shall be so coordinated that external flashover shall not occur due to application of any impulse of switching lighting voltage up to the maximum design value for arrestor. The arrestors shall not fail due to contamination. The 33kV arrestors housing shall be designed for pressure relief class as given in Technical Parameters of the IEC 60099.
Sealed housings shall exhibit no measurable leakage.
 
 
 
 
 
 
 
7.3 Arrestor Mounting
The arrestors shall be suitable for mounting on 4 pole/2 pole structure used for pole/ plinth mounted transformer and for incoming and outgoing lines.
 
7.4 Fittings & Accessories
The lightning arrestor shall be complete with insulating bases, fasteners for stacking units along with clamp & terminal connectors and inbuilt disconnector.
The terminals shall be non-magnetic, corrosion proof, robust and of adequate size and shall be so located that incoming and outgoing connections are made with minimum possible bends. The top metal cap and base of lighting arrestor shall be galvanized. The line terminal shall have a built in clamping device, which can be adjusted for both horizontal and vertical take off.
 
8.0 Design considerations
Lightning arresters shall withstand the voltages and the resulting currents through them with a sufficiently high reliability taking into account pollution and other site matters. In each system such voltage stresses are (see IEC 60071-1)
-operating voltage
-temporary overvoltage
-slow-front overvoltage
-fast-front overvoltage
 
8.1 Rated Voltage
The maximum permissible r.m.s value of the power frequency voltage between the arrester terminals, at which it is designed to operate correctly as established in the operating duty test.
8.2 Nominal Discharge Current
This is the current which is required to initiate the flow of current in the operating duty test and to establish the protective level of the arrester for lightning overvoltage. This value shall be such that the arrester provides and guarantees safety to the system it is protecting.
8.3 Protective Level
The lightning impulse protective level of the surge arrester is the maximum of the following values:
-the standard lightning impulse spark over voltage.
-the residual voltage at nominal discharge current.
These values should be as per the IEC60099-1.
8.4 Long duration discharge class
A number related to the energy absorption capability of an arrester to discharge long lines. Increasing class numbers (see table 1) indicate increasing system voltages and line length and decreasing surge impedance and overvoltage factors. Tenderers should indicate the class basing on the given table on the technical guarantee schedule.
 
 
8.5 Pressure release class
A number related to the capability of an arrestor to withstand internal fault currents after a failure without violent shattering of the housing. Reference is made to clause 8.7 of IEC60099-1.
8.6 Polluted Housing
Pollution on the arrester housing may cause sparkover or temperature increase of grading components in gapped arresters and high temperature increase of the varistors in metal oxide arrestors. To prevent arrestor failures in polluted areas, arrestors able to withstand failures in polluted areas, arresters able to withstand the relevant polluted conditions have to be chosen. The arresters under this specification should withstand the medium pollution stresses according to pollution level 2 of IEC 60071-2.
8.7 Earth Fault
These cause over voltages which occur in a large part of the system. Guidance for the determination of temporary overvoltage amplitudes should be as per the BN EN 60099-5 1997. The duration of the overvoltage corresponds to the duration of the fault (until fault clearing). The design must withstand the 1s time duration for earthed neutral systems, and longer durations for other special conditions. 
8.8 Load rejections
Voltage surges that occur during load disconnections should be taken into consideration during the design. The design should also look into the Ferranti effect for long lines, harmonic over voltages, resonance effects and all other aspects that bring about temporary surges.
 
9.0 Drawings and Documents
 
Bidder to submit along with the bid the drawings, diagrams, dimensions and brochures of the arrestor.
 
10.0 Type tests and compliance with specification.
 
A type test certificate or type test results and compliance statement on a clause by clause basis shall be provided with the bidding document.
 
 
 
 
 
 
 
 
 
 
 
 
11.   TECHNICAL GUARANTEE SCHEDULE: LIGHTNING ARRESTERS
            Please complete this schedule by stating the actual tendered lightning arrester specification in the column labelled Guaranteed Value.