tel–type surge arresters - lbt

TEL–TypE surgE arrEsTErsTechnical manual

� TEL-type surge arrestersTechnical manual

Contents

General information 3Introduction 3Product range 4Arrester construction 4Functioning of arrester 5Technical specification 6

SAI(O)/TEL - Х - 250 6SAI/TEL - Х- 550 7

Overall drawings 8SAI(O)/TEL-X-250 8SAI/TEL-X-550 9

Application guide 10Recommendations on Selection of Surge Arrester 10Selection of maximum continuous operating voltage 10Selection of nominal discharge current 10Selection of protection level 10Selection of energy capability 10Selection of short-circuit current 11Selection of creepage distance 11Protection distance of arrester 11Protection of motors 12Protection of transformers 12Protection of cable networks 12Protection of equipment switched by VCB 12Mounting of SAI(O)/TEL-X-250 and SAI/TEL-X-550 13Visual inspection 15Maintenance 15Disposal 16Warranties 16Delivery set 17Ordering 17

Appendix 1 Terms and definitions 18

Appendix 2 Safe operation zones for TEL-type vacuum circuit breakers operating

with transformers 19

List of changes 20

�TEL-type surge arresters Technical manual

General information

IntroductionNon-linear TEL-type metal-oxide surge

arresters are used as the main protective devices for the

equipment in medium- and high-voltage substations from

both switching and lightning overvoltages The newest

achievements in arrester technology together with the serv-

ice experience of surge arresters have been gathered and

analyzed to improve the performances of TEL-type surge ar-

resters, which can be applied instead of gapped arresters in

the designing and modernization of power substations and

installations

The product range of TEL-type arresters is as follows:LSAI(O)/TEL-X-250 is designed for the reliable

protection of 6-10 kV systems with isolated or

compensated neutral They can be used in distri-

bution networks for the protection of transform-

ers and motors Both indoor and outdoor arrest-

ers are available LSAI/TEL-X-550 is recommended for the protec-

tion of critical equipment at rating 3-10 kV

SAI/TEL-3 0-550 has been developed especially

for the protection of energy supply installations

of railway facilities and available for internal ap-

plications Other applications of 3 kV arresters,

e g in overhead lines to protect high-frequency

line traps, are also possible SAI/TEL-X-550 with

other voltages can only be used indoors to pro-

tect transformers of arcing furnaces as well as

the insulation of cable networks, motors etc

All the surge arresters mentioned above can operate in

a temperature range of -60…+55°C at an altitude of up to

1000 m above sea-level

Since the nineties TEL-type surge arresters have proved

themselves to be reliable, maintenance-free and safe pro-

tective devices Today over 200,000 TEL-type surge arresters

protect different types of equipment all over the world

In addition to the well-known advantages of MO surge

arresters, such as the absence of follow current, continu-

ous connection to the line and energy capability, TEL-type

metal oxide surge arresters exhibit the following extra ad-

vantages as a result of the unique molding technique and

the excellent long term stability of resistors:Lno maintenance is requiredLunlimited mechanical lifeLreliable limitation of overvoltagesLwide range of operating voltagesLexplosion safety and seismic stabilityLhigh reliability in serviceLhigh resistance to atmospheric pollutionLfit easily into switchgearsLsmall weight and dimensions

TEL-type surge arresters completely satisfy the require-

ments of IEC 60094-4 and GOST 163576-83

The whole range of TEL-type arresters is shown in the picture below

SAI(O)/TEL-X-250 SAI/TEL-X-550


Product rangeTEL-type surge arresters differ in rated voltage, long duration current impulse, creepage distance and di-

mensions The complete range of products complies with the following Table

DesignationSystem volt-

age of network, kVLong duration cur-

rent impulse, АCreepage distance, mm, not less than

Height, mm, not more than

Weight, kg, not more than

SAO/TEL - 6 9 - 250 6 250 235 115 0 9

SAO/TEL - 12 0 - 250 10 250 370 160 1 3

SAI/TEL - 6 0 - 250 6 250 130 95 0 7

SAI/TEL - 6 6 - 250 6 250 130 95 0 7

SAI/TEL - 6 9 - 250 6 250 130 95 0 7

SAI/TEL - 7 2 - 250 6 250 130 95 0 7

SAI/TEL - 10 5 - 250 10 250 180 125 0 9

SAI/TEL - 11 5 - 250 10 250 180 125 0 9

SAI/TEL - 12 0 - 250 10 250 180 125 0 9

SAI/TEL - 4 0 - 550 3 550 135 95 1 1

SAI/TEL - 6 0 - 550 6 550 135 95 1 1

SAI/TEL - 6 9 - 550 6 550 135 95 1 1

SAI/TEL - 7 2 - 550 6 550 135 95 1 1

SAI/TEL - 10 5 - 550 10 550 205 140 1 5

SAI/TEL - 11 5 - 550 10 550 205 140 1 5

Arrester constructionThe TEL-type surge arrester is a high volt-

age device consisting of piled up MO resistors placed inside

insulating housing The extreme non-linearity of volt-am-

pere characteristic of MO resistors allows the arrester to be

continuously connected to the line and guarantees deep

limitation of overvoltages

Tavrida Electric produces surge arresters using metal-

oxide resistors from world-known producers which exhibit

excellent long-term stability Due to the technological dis-

persion, the parameters of each resistor are kept in the com-

puter database The computer database is used to select the

resistors, which in each case will be used to create arrester

the excellent characteristics

Construction of SAI(O)/TEL-X-250 and SAI/TEL-X-550


In order to produce SAI(O)/TEL-X-250 and SAI/TEL-X-

550, the stack of resistors is placed between terminals and

shedded with the insulating housing that provides both

the tracking and atmospheric resistance of the arrester

The manufacturing process of such arresters is unique and

ensures both the mechanical and the insulating strengths

Such a construction has proved itself while being used in

different service conditions, including regions with high at-

mospheric pollution Arresters of these types have the same

construction and differ in creepage distance only SAI(O)/

TEL-X-250 is designed for both indoor and outdoor use, SAI/

TEL-X-550 is for indoor use only The arresters of both types

are essentially similar in construction and differ in creepage

distances only

TEL-type surge arresters have the advantage that that

there is no gas volume in the arrester; therefore no internal

insulation flashover can occur

Functioning of arresterUnder normal conditions an extremely

small capacitive current (significantly less than 1 mA) flows

through the arrester When an overvoltage wave appears in

the network, the arrester goes into conductive state and

prevents the voltage further increasing After the voltage

returns to the normal level the surge arrester reverts back

to a non-conductive state

The effect of a metal-oxide surge arrester on an over-

voltage wave is illustrated in the picture below


Technical specificationGeneral terms and definitions are given in Appendix 1 Applicable standards: IEC 60099-4, GOST 163576-83

SAI(O)/TEL - Х - 250

Parameters SAI(O)/TEL - Х- 250

6 0 6 6 6 9 7 2 10 5 11 5 12 0

System voltage of network, kV 6 6 6 6 10 10 10

Maximum continuous operating voltage, kV 6 0 6 6 6 9 7 2 10 5 11 5 12 0

Nominal discharge current 8/20 μs, kА 10 10 10 10 10 10 10

Residual voltage, kV, not more than:

- for switching current impulse

125 А, 30/60 μs 14 3 15 4 16 2 16 9 24 8 26 9 29 7

250 А, 30/60 μs 14 6 15 8 16 5 17 2 25 4 27 6 30 4

500 А, 30/60 μs 15 0 16 2 17 0 17 7 26 1 28 3 31 3

- for lightning current impulse

5000 А, 8/20 μs 17 7 19 1 20 0 20 8 30 7 33 3 36 9

10000 А, 8/20 μs 19 0 20 5 21 5 22 4 33 0 35 8 39 6

20000 А, 8/20 μs 21 2 22 8 24 0 25 0 36 7 39 9 44 1

- for high current impulse

10000 А, 1/10 μs 21 3 22 9 24 1 25 1 36 9 40 1 44 3

Energy input capacity, kJ/kV, not less than 3 6 3 6 3 6 3 6 3 6 3 6 3 6

High current impulse 4/10 μs, peak value, kА 100 100 100 100 100 100 100

Maximum short circuit current, kА 5 5 5 5 5 5 5

Maximum cantilever load, N 305 305 305 305 305 305 305

Power frequency withstand voltage ver-

sus time characteristic of SAI(O)/TEL-X-250

for quasi-static overvoltages:

1 — arrester, being preloaded with en-

ergy of 3 6 kJ/kV;

2 — arrester without preloading


SAI/TEL - Х- 550

ParametersSAI/TEL - Х- 550

4 0 6 0 6 9 7 2 10 5 11 5

System voltage of network, kV 3 6 6 6 10 10

Maximum continuous operating voltage, kV 4 0 6 0 6 9 7 2 10 5 11 5

Nominal discharge current 8/20 μs, kА 10 10 10 10 10 10

Residual voltage, kV, not more than:

- for switching current impulse

125 А, 30/60 μs 8 9 13 3 15 3 15 9 23 2 25 4

250 А, 30/60 μs 9 4 14 0 16 1 16 8 24 5 26 9

500 А, 30/60 μs 9 6 14 4 16 6 17 3 25 2 27 6

- for lightning current impulse

5000 А, 8/20 μs 11 5 17 2 19 7 20 6 30 0 32 8

10000 А, 8/20 μs 12 5 18 7 21 5 22 4 32 7 35 8

20000 А, 8/20 μs 14 0 21 0 24 1 25 1 36 6 40 1

- for high current impulse

10000 А, 1/10 μs 14 4 21 5 24 7 25 8 37 6 41 2

Energy input capacity, kJ/kV, not less than 5 5 5 5 5 5 5 5 5 5 5 5

High current impulse 4/10 μs, peak value, kА 100 100 100 100 100 100

Maximum short circuit current, kА 20 20 20 20 20 20

Maximum cantilever load, N 300 300 300 300 300 300

Power frequency withstand voltage ver-

sus time characteristic of SAI/TEL-X-550

for quasi-static overvoltages:

1 — arrester, being preloaded with en-

ergy of 5 5 kJ/kV;

2 — arrester without preloading


Overall drawings

SAI(O)/TEL-X-250

SAO/TEL-6 9-250 SAO/TEL-12 0-250

SAI/TEL-6 0-250SAI/TEL-6 6-250SAI/TEL-6 9-250SAI/TEL-7 2-250

SAI/TEL-10 5-250SAI/TEL-11 5-250SAI/TEL-12 0-250


SAI/TEL-X-550

SAI/TEL-4 0-550SAI/TEL-6 0-550SAI/TEL-6 9-550SAI/TEL-7 2-550

SAI/TEL-10 5-550SAI/TEL-11 5-550

10 TEL-type surge arrestersTechnical manual

Application guide

Recommendations on Selection of Surge ArresterThe correct choice of arrester character-

istics for each application guarantees further effective

protection of the equipment and always strikes a careful

balance between the protection level and the safety of the

arrester Obviously, the complete data about actual stresses

that occur in the network and effect the arrester have to

be obtained Requirements and recommendations of corre-

sponding standards shall also be taken into consideration in

each specific case

The parameters of the SA have to be selected taking

into account purposes, required protection levels, environ-

mental conditions and the type and parameters of the net-

work Thus, the following main electrical parameters have

to be evaluated:Lmaximum continuous operating voltage;Lnominal discharge current;Lresidual voltages for switching current and light-

ning current impulsesLenergy absorptionLshort-circuit currentLcreepage distance

Selection of maximum continuous operating voltageIn networks with isolated neutral, or in

which the compensation of capacitive currents is used and

long-term single-phase earth faults are allowed, the maxi-

mum continuous operating voltage of the arrester shall be

selected equal to the maximum operating voltage of the

network or equipment to be protected

If the duration of single-phase earth fault is limited,

e g with relay protection systems, the maximum continu-

ous operating voltage for the phase-to-earth connected ar-

resters shall be at least

Uc=Us/T(t)

Where T(t) = U/Uc is the ratio of power frequency al-

lowable voltage, which may be applied to the arrester for

a period of t, to the maximum continuous operating volt-

age of the arrester T(t) shall be taken from power frequency

voltage versus time curves for the longest allowable time of

the network single-phase earth fault

In systems with effectively earthed neutral, surge ar-

resters should be connected between phase and earth In

this case the maximum continuous operating voltage of the

arrester shall be selected equal to or 5-10 % higher (to take

into account possible higher harmonics) than the maximum

operating phase voltage of the system

Selection of nominal discharge currentSurge arresters with nominal a discharge

current of 5 kA can be applied in 6-10 kV networks instead

of gapped arresters and in other cases if the distance be-

tween arresters in the network is shorter than 5 km In all

other cases surge arresters with a nominal discharge current

of 10 kA should be used

Selection of protection levelAfter the maximum continuous operat-

ing voltage is chosen, the protection level of the arrester

when switching and lightning overvoltages occur shall be

verified The peak values of residual voltages for switching

current impulse and for nominal discharge current shall be

15-20 % less than the insulation level of equipment to be

protected, provided that the level of switching current im-

pulse is equal to that of the long duration current impulse

Selection of energy capabilityThe surge arrester shall be able to absorb

the energy of overvoltages expected in service, which ap-

pear with lightning discharges and after switching over-

head or cable lines and condenser banks

No additional verification and calculation of energy ca-

pability shall be made because it is proved by the high cur-

rent impulse test included in the type tests procedure

11TEL-type surge arresters Technical manual

The energy W (in kJ), which shall be absorbed by the ar-

rester in an overhead line, is

W=2uUru(U–Ur)uTw/Z

Where Ur — residual voltage for switching current im-

pulse

U — expected peak value of switching overvoltage or

charging voltage of line

Tw — overvoltage wave propagation time, Tw=L/v

L — length of overhead line

Z — wave impedance of overhead line

When switching a condenser bank or a cable line, the

energy to be absorbed by the arrester, provided that the ov-

ervoltage level is 3 p u , is

W=3uСu(Us2–0 52uUc2)

Where C — capacity of a condenser bank or a cable line

to be switched, μF

The results shall be compared with the energy capabil-

ity of the chosen arrester Manufacturers usually specify the

maximum energy absorption that is verified during type tests

and expressed in kJ/kV (rated voltage) It shall be taken into

account that in accordance with IEC 60099-4 surge arresters

which correspond to line discharge class 1 (with long duration

current impulse up to 400 A) shall be tested using single 100

kA high current impulse, unlike arresters of other classes that

shall be tested with two long duration current impulses

Selection of short-circuit currentThe short-circuit current of an arrester shall

be 10% greater than its expected internal short-circuit cur-

rent, taking into account the type of connection and the lo-

cation of the arrester as well as the type of system neutral

Selection of creepage distanceThe creepage distance shall meet the re-

quirements of IEC 60694, taking into account a degree of

atmospheric pollution

Protection distance of arresterEfficiency of protection depends not only

on the residual voltage of an arrester but also from the dis-

tance between the arrester and equipment to be protected

The reasons for the overvoltage level increasing are as

follows:

1) Reflection of traveling waves from the line termi-

nals

2) An increase in the voltage across mounting conduc-

tors, which exhibit inductive resistance when high frequen-

cy currents pass through them

The protective distance of the arrester can be roughly

estimated with the following formula:

U=Ur+(2uSuL)/v,

Where U — voltage on equipment to be protected in

kV,

Ur — residual voltage of arrester in kV,

S — overvoltage wave steepness in kV/μs,

L — distance between arrester and equipment to be

protected (in m),

V - speed of traveling wave (300 m/μs for overhead

lines, 150 m/μs for cable lines)

In all cases the distance between an arrester and the

equipment to be protected should be as short as possible

(not longer than 3-6 m)

As a rule, non-linear surge arresters are connected in

parallel with equipment, i e between phase and earth

1� TEL-type surge arrestersTechnical manual

Protection of motorsHigh-voltage motors, as a rule, cannot be

subjected to stresses caused by lightning

However, the insulation of motor windings shall be

protected against switching overvoltages that occur for in-

stance, at disconnection of starting motors For this pur-

pose the phase-to-earth connection of surge arresters that

is usually used provides effective protection of motor insu-

lation relative to earth

If phase-to-phase insulation of the stator has to be pro-

tected, the additional arresters with a maximum continuous

operating voltage, not less than the system voltage of the

network, should be connected in a delta

In both cases surge arresters should be located as close

to the motor terminals as possible, e g in a terminal box

or connected to a power supply cable at a distance of 3-

5 m from its terminals Moreover, mechanical, temperature

stresses on the arrester shall not exceed the specified lev-

els SAI/TEL-X-550 are recommended in these cases

If the arrester cannot be mounted in close vicinity to

the motor, it can be installed parallel with the circuit break-

er, provided the length of the cable is up to 200 m In this

case a disconnector shall be applied to provide guaranteed

de-energisation of the motor during maintenance

Protection of transformersThe protection of transformers against

lightning overvoltages is usually provided by arresters con-

nected between phases and earth Both high-voltage and

low-voltage windings of transformers shall be protected

as up to 40 % of overvoltage can be induced into the low-

voltage winding due to the capacitive couplings For this

purposes the application of SAI(O)/TEL-X-250 is recom-

mended

If only the secondary winding of the transformer is pro-

tected, SAI(O)/TEL-X-250 can be connected to this winding

only

Protection of cable networksThe cables connecting an overhead line

with substation equipment are subjected to stresses caused

by lightning In the case of the short cables, arresters can

be connected directly to cable terminals from the overhead

line side In this case the application of SAI(O)/TEL-X-250

is recommended

With the cable length of more than 70 m for 6 kV net-

works and more than 30 m for 10 kV networks both ends

of the cable should be protected For this, the arresters

are connected between the phase conductor and the cable

shield in close proximity to the cable connectors

Cables, which are not connected to an overhead line,

should be protected against switching overvoltage, which is

often the reason for the damage of cable insulation The ap-

plication of arresters decreases the degree of cable insulation

deterioration, reduces the number of multiple failures at sin-

gle-phase earth faults and improves the reliability of protect-

ed equipment In this case SAI/TEL-X-550 should be used

Protection of equipment switched by VCBWhen a vacuum circuit breaker interrupts

small inductive currents, e g if there are non-loaded trans-

formers and decelerated or starting motors, the appearance

of dangerous overvoltages is possible with some combina-

tions of feeder parameters and VCB characteristics

Surge arresters, when installed in feeders with VCB, con-

strict overvoltages caused by current chop and voltage es-

calation, reduce the amount of resignations and eliminate

the possibility of overvoltages resulting from virtual current

chop

When a VCB is used to energize a powerful motor, surge

arresters should be installed in parallel with the VCB contacts,

provided that the maximum continuous operating voltage of

arresters is not less than the system voltage of the network

This method allows overvoltages affecting the motor insula-

tion fall to a level lower than that provided by oil and small-

oil volume circuit breakers However, a disconnector shall be

used in this case Such a connection of surge arresters pro-

vides effective protection at cable length of up to 200 m only

In this case the use of SAI(O)/TEL-X-250 is recommended

With longer cables the arresters should be installed between

the phase and earth both near the motor and from the load

side of the VCB In this case SAI/TEL-X-550 can be used

1�TEL-type surge arresters Technical manual

horizontal line horizontal line

Operation position of SAO/TEL-X-250 Operation position of SAI/TEL-X-250 (550)

The necessity of the use of surge arresters to protect

powerful transformers switched by VCB can be determined

with the graphs of safe operation zones in Appendix 2,

where the no-load current of the transformer is a reference

value; the capacity of the feeder is taken as equal to that of

connecting cables

If the intersection point is put in the shaded area,

the surge arresters connected between phase and earth

should be installed from the load side In the graphs of

safe operation zones the overvoltage level equal or higher

than the test voltage for the insulation of transformers is

considered to be dangerous For this purpose the appli-

cation of SAI(O)/TEL-X-250 or SAI/TEL-X-550 is recom-

mended

Mounting of SAI(O)/TEL-X-250 and SAI/TEL-X-550SAI(O)/TEL-X-250 or SAI/TEL-X-550 should

be mounted in accordance with the present Manual

TEL-type surge arresters need no special mounting fa-

cilities and can be fixed with M10 bolts (studs) only SAO/

TEL shall be positioned vertically at an angle of up to 45°

with the axis vertical Arresters for indoor application are

not sensitive to operation position

When selecting the location of the arrester, the pres-

ence of equipment, which generate heat under working con-

ditions, shall be taken into consideration Thus, the tem-

perature in the vicinity of such equipment can be higher

than the ambient temperature

The arrester shall be connected to busbars by bolts (or

studs) made of corrosion-resistant steel or covered by cor-

rosion-resistant coating The contact surface shall be pre-

pared around the bolt (stud) to provide connection of con-

ductors (busbars) The contact surface shall also be made

of corrosion-resistant steel or covered by corrosion-resist-

ant coating The required connection area shall be provided

with the help of washers To prevent the slackening of the

bolt (stud) lock-nuts or spring washers should be used


The tightening torques of the bolts (studs) shall be 25±5 N•m

To exclude mechanical overloads during installation

and service life the flexible joint, e g a steel strip 20u1

mm, should be used from one side of the arrester Wires with

cross-section 1 5 sq mm can be used, except for connection

of SAI/TEL-550 with steel wires when wires of not less than

4 sq mm shall be used

The arresters for outdoor installation should be con-

nected with the help of a flexible bare conductor with cross-

section of 5–6 sq mm

Cantilever, torque and tensile forces at bus arrange-

ments shall not exceed 300 N When mounting the arresters

any static loads shall be eliminated Outdoor arresters can

be subjected for a short time to a load of up to 305 N caused

by conductor tension at a wind velocity of 40 m/s and icing

of up to 20 mm thickness

With the arresters for internal installation, the busbars

shall be chosen long enough to avoid external heating of

the arrester to above 55°C from the current-carrying busbar

side

The application of a steel strip (20u1 mm) with a tem-

perature gradient of about 70°C per 50 mm of length is rec-

ommended It is allowed to connect surge arresters with in-

sulated 100 mm wires or longer In addition, the conductors

between the phases and the arresters shall be not longer

than 400 mm

A short-term increase (up to 8 hours) of ambient tem-

perature up to 80°C is allowable The distance between the

arrester sheds and earthed constructions shall be not less

than that specified in the corresponding standards for cur-

rent-carrying parts

The cross section of the earthing busbar has to be cho-

sen taking into consideration the mechanical strength of

the connection The earthing busbar shall be connected

with the ground grid by the shortest route


To exclude galvanic corrosion the application of alumi-

num or galvanized steel wires is recommended It is allowed

to use standard terminals intended for compression or sol-

der joints

In case of internal installation, the application of ad-

ditional insulating cap is allowed, provided it laps less than

25% over surge arrester’s housing Actions shall be taken

to make sure that the creepage distance of surge arrester is

similar to the specified one

Visual inspectionBefore the installation of arresters no spe-

cial tests have to be carried out

The only visual inspection shall be performed to make

certain that the housing have no damages, scratches and

spots and there is no corrosion on arrester’s terminals

(flanges)

Suitability of the arresters for the application in given

network shall be proved by comparison of data marked on

arrester’s housing to order data

MaintenanceTEL-type surge arresters are inherently

maintenance free and require no tests when they are in

service

During mounting the arresters and while in use custom-

ers should follow corresponding safety regulations

When high voltage tests are carried out on the substa-

tion equipment, the arresters should be disconnected to

avoid damaging the resistors

The surface of arresters, which serve in a highly pol-

luted atmosphere, should be cleaned periodically if such a

procedure is required for other substation equipment This

should be done with a dry cloth, which does not leave fibres

Alternatively, the arresters can be washed with soapsuds

Highly polluted places can be cleaned using a cloth soaked

in alcohol The use of oil, petrol, benzene, acetone and wire

brushes is not permitted

Malfunction tracing

N Malfunction Possible reason Tracing procedure Recommended actions

1 An M10 bolt cannot be screwed into the hole of an arrester’s terminal

Foreign particle in the thread Gauge M10 Remove foreign particle

Bolt with non-standard thread

Gauge M10 Replace bolt

Bolt longer than 10 mm Trammel Replace bolt

2

Deposits on the surface of ar-rester housing and corrosion of terminals Arrester housing is not damaged

Violation of storage or service conditions

Visual inspectionClean arrester housing or scour off corrosion

3

Arrester housing and/or ter-minals (flanges) are partially melted Resistors are not damaged

Non-observance of tempera-ture range

Visual inspection Disassem-ble arrester and check charac-teristics of resistors

Replace arrester Check whether it is mounted cor-rectly Check the distance from arrester to nearby earth-ing constructions and arrest-ers in other phases

Effect of arcing

4 Arrester housing is complete-ly melted Resistors are not damaged

Non-observance of tempera-ture range

Visual inspection Disassem-ble arrester and check charac-teristics of resistors

Replace arrester Check whether it is mounted cor-rectly Check whether there is a heat source close to ar-rester

Long-duration arcing earth fault


N Malfunction Possible reason Tracing procedure Recommended actions

5 Residual deformation caused by bending or tension

Presence of residual mechani-cal loads due to in-correct mounting

Visual inspection Replace arrester Eliminate residual mechanical loads

6 Arrester housing is melted completely Resistors are damaged

Long-duration arcing earth fault

Visual inspection Replace arrester

7 Damage of arrester housing caused by explosion

Energy overstress Ferromag-netic resonance

Visual inspection

Replace arrester Check whether the parameters of ar-rester correspond with those of network

Wrong choice of arrester with lower maximum continuous operating voltage

8 Presence of erosive tracks or craters on housing, local fu-sion of housing

Conductive inclusions in ar-rester housing (Manufactur-er’s fault)

Visual inspection

Replace arrester

The use of arrester in region with abnormal atmosphere (ambient air contains con-ductive dust)

Replace arrester with that corresponding to service con-ditions

DisposalSurge arresters do not contain any ma-

terials that are hazardous for environment or personnel

No special methods of disposal are required

WarrantiesThe manufacturer guarantees the compli-

ance of TEL-type surge arresters when used in accordance

with the present Technical Manual

The expected lifetime of TEL-type surge arresters is 25

years The warranty period of TEL-type surge arresters lasts

for three years after delivery

The warranty is only valid for modules if the application

conditions specified in the current Manual have been met

Under no circumstances is Tavrida Electric responsible for

indirect losses associated with the failure of the arresters


Delivery setThe delivery set for surge arresters of each type are shown in Table below

Type Amount of arresters in a package Acceptance report

SAO/TEL-X-250 1 1

SAI/TEL-X-250 3 1

SAI/TEL-X-550 3 1

OrderingThe full title of surge arrester should be

specified when ordering

Below is an example of an order for a surge arrester for

a network with a system voltage of 10 kV, a maximum con-

tinuous operating voltage of 11 5 kV and a maximum long-

term current in the network of 550 A, for indoor use:

Surge arrester SAI/TEL-11 5-550 — 300 pcs


Appendix1.Terms and definitions

Metal-oxide surge arrester — An arrester having non-linear metal-oxide resistors connected in series without

any integrated spark gaps and enclosed into an insulating housing

Non-linear metal-oxide resistor — The part of the surge arrester which by its non-linear voltage versus current

characteristics acts as a low resistance to overvoltages and as a high resistance

at normal power frequency voltage

Max continuous operating voltage — The designated permissible rms value of power frequency voltage that may be

applied continuously between the arrester terminals

Long current withstand capability — Ability of an arrester to withstand 18 steep current impulses with duration 2

ms These impulses shall not cause puncture or flashover

Residual voltage — The peak value of voltage that appears at the arrester terminals during the pas-

sage of lightning or switching current

Lightning current impulse — An 8/20 current impulse

Switching current impulse — A discharge current impulse having a virtual front time greater than 30 μs but

less than 100 μs and a virtual time to half value on the tail of roughly twice the

virtual front time

High current impulse — The peak value of discharge current having a 4/10 impulse shape which is used

to test the stability of the arrester on direct lightning strokes

Reference current of an arrester — The peak value of the resistive component of a power frequency current speci-

fied by the manufacturer and used to determine the reference voltage of the

arrester

Reference voltage of an arrester — The peak value of power frequency voltage which shall be applied to the ar-

rester to obtain the reference current


Appendix�.Safe operation zones for TEL-type vacuum circuit breakers operat-ing with transformers

�0TEL-type surge arresters Technical manual

List of changes

Page Implemented changes Reason Date

14The upper limit to the length of isolated wire, connecting SA to power line, is removed

Correct misprint 26 12 2006

�1TEL-type surge arresters Technical manual

tel–type surge arresters - lbt

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