فحص الكابلات

Draft Proposal: Saudi Electric Company (SEC)

Task 6 - Item 1.4: 33 kV and 13.8 kV Cable Termination Failure Investigation Study

Test Plan - Methodology Task Series 1000 Shipping / Unpacking MHI assumes that SEC will ship the cables to Manitoba Hydro as per the precautions noted below. Upon arrival, MHI staff will unpack the cable samples, and will prepare them for the inspections and tests. As per the Statement of Work, SEC will supply the following cable / termination samples:

A. Five failed cable terminations B. Three sound cable terminations removed from service (Min length = 2 meters) C. Two new Raychem termination kits

In addition, MHI requests that SEC also supply the following cable / termination samples:

I. Three kits of the next highest voltage class rating to terminate the opposite end of the sound cable terminations removed from service (as supplied above in “B”)

II. Two pieces of cable that will be terminated with the two new Raychem termination kits (as supplied above in “C”)

III. Two additional kits of the next highest voltage class rating to terminate the two additional pieces of cable (as supplied above in “II”)

Precautions to be taken when packaging cables: In order to obtain meaningful measurements of surface contamination it is important that the terminations be protected during transport. This can be accomplished by supporting each termination inside a clean polymeric tube that encloses all the Raychem sheds. Only the tips of the sheds should touch the inside surface of the tube. Task Series 2000 Preliminary Testing and Contamination Testing 2100 ESDD & NSDD Tests of Surface In-Service Cable Terminations ESDD (equivalent salt deposit density) is a measurement of the severity of salt contamination Sa = (5.7 σ20)

1.03 where Sa = salinity in kg/m2

σ20 = volume conductivity in S/m at 20oC ESDD = Sa V mg/cm2

A where V = volume in mL

A = sampled area in cm2

Reference IEC 60507 NSDD (non-soluble deposit density) is a measurement of non-soluble contamination NSDD = net mass of contaminant (grams) Area (cm2) Samples having ESDD >10 μg/cm2 will be forwarded for further Chemical Analysis (see Task 4100-1) to determine the elements present.

2200 Hydrophobicity Tests Hydrophobicity is a measurement of the wettability of an insulator surface. MHI will measure the Hydrophobicity according to IEC standard TS 62073 - Method C (spray method). Tests will also be made on the new Raychem terminations for comparison purposes. 2300 Visual Inspection & Dissection & Dimensional Analysis of Failed Terminations This task is intended to examine the failed terminations both externally and internally for any common factors that can be associated with the failure. This task should indicate if the terminations are properly sized, properly installed, and a general evaluation of the cable preparation. The installation of the terminations will be compared to the manufacturer’s appropriate instructions. In specific, the Visual Inspection will examine the failed terminations for the following external cues:

Location of failure Evidence of tracking Indication of improperly installed tubes Indication of excessive heat applied to the tubes

The Dimensional analysis & dissection of the failed terminations will examine the following: Placement of the insulating tubes Placement of the stress relief tubes Cable preparation cutbacks Evidence of internal heating Evidence of tracking on any internal interface General evaluation of cable preparation techniques

2400 Preliminary Microscopic Material Analysis The condition of the surface of the terminations will be examined and recorded using a low magnification microscope that is ordinarily used in the examination of water trees in XLPE cables.

Microscope & camera Bowtie water trees in 15 kV XLPE If required, further microscopic analysis can be performed as part of Task 4000.

Task Series 3000 Electrical Testing 3100 Cable Preparation This task is to prepare both the three service aged cables and the two new cable terminations for electrical tests. In order to perform the electrical tests, the other end of the service aged cables will to be terminated with additional kits supplied by SEC, rated at least one voltage level higher than the termination being tested. The new termination kits supplied by SEC will also be installed on appropriate cable, with the opposite ends terminated with kits, again one voltage level higher.

3200 Partial Discharge Tests The partial discharge tests will be made in accordance with IEEE Std 48. This specifies:

Insulation Class kV

Conditioning kV rms

PD Measurement kV rms

PD Limit pC

15 15.6 13.0 5 35 36.0 30.0 5

The conditioning voltage is maintained for between 3 s and 60 s and partial discharge is measured as the voltage is lowered to the specified level for PD measurement. 3300 AC Voltage 1 minute Dry Withstand MHI will perform this test according to IEEE Std 48. This standard specifies a 1 minute dry withstand test using 60 Hz voltage at:

50 kV rms for terminations rated 15 kV 90 kV rms for terminations rated 35 kV

3400 Lightning Impulse Tests Each intact termination, both service-aged and new, will receive a lightning impulse voltage test in accordance with IEEE Std. 48, Section 8.4.1.6, at a prescribed BIL of 200 kV for the 35 kV class terminations and 110 kV for the 15 kV class terminations. The impulse voltage waveform will be a nominal 1.2 x 50 s wave in accordance with IEEE Std. 4 with exceptions noted as per IEEE 48, Sec. 8.4.1.6. Ten consecutive impulses of each polarity will be applied with the conductor temperature of the cable at ambient and again at an elevated temperature corresponding to the maximum emergency operating conductor temperature*. The test procedure will be as specified in IEEE Std. 82. The test report shall include the voltage wave shape and polarity of each impulse, wave shape at the maximum positive and negative impulse voltage, ambient conditions, cable temperature, and a record of all failures and test interruptions. Significant variation between the withstand characteristics of the new and service-aged terminations may indicate installation deficiencies, abnormal service ageing, or contamination degradation.** * Feasibility to be determined based on current required to sufficiently heat the conductors. We need to know more about these cables. Worst case -- our "elevated temperature impulse test" is based on maximum achievable in the lab and may be short of emergency loading levels. This may be sufficient to learn something. If we see a problem at less that the maximum temp, then we know that problems are likely at the max loading. ** NB: this same statement could be said for all the dielectric tests.

3500 Resistance Tests For this task the contractor will perform micro ohm meter readings between cable conductor and the compression connector in order to verify the connection between the two. These measurements will be taken on the failed terminations, the service aged terminations and the new kits. Measurements will be taken on the service aged and new terminations before any electrical testing. These will then be compared to measurements obtained after the electrical testing is complete. This comparison will indicate if the connection is susceptible to any degradation due to the electrical and thermal stresses of testing regime. 3600 Volt Amp Test on Stress Control Material A direct voltage (dc voltage) will be applied across the length of the stress control tube of the termination. The voltage will be raised in steps of 10% up to the maximum specified in IEEE Std 48 for the 15 minute dc voltage withstand test. The current drawn by the stress control tube will be measured at each step. The maximum test voltage will be:

75 kVdc for terminations rated 15 kV 140 kVdc for terminations rated 35 kV

A test will be made on at least one new Raychem termination for comparison purposes. Task Series 4000 Chemical Analysis 4100 Contamination Analysis If the inspection of the cable samples, microscopic examination of same, electric tests or any other sample assessment tool gives any indication that the failures may be partly or totally caused by contaminants on the tubes or an aggressive chemical environment, MHI’s chemical laboratories would try to identify the chemical contaminants contributing to this problem.

Most likely mechanisms of cable deterioration are:

1. Deterioration by Salt Exposure - Common contaminants contributing to this deterioration could be common salt or mixtures of contaminants containing chlorides, sulfates, nitrates, etc. An area of cable will be rinsed with pure water. The rinsate will be analyzed for metals by Inductively Coupled Plasma (ICP) and for anions by Ion Chromatography (IC). If the contaminant is found in large enough quantities, it may be best to physically remove a sample of the contaminant from the cable and send it to the lab for analysis by the above testing techniques. The reason for doing this rather than obtain a rinsate from the sample is that some contaminants may not be readily soluble in pure water. Other solvents used in the lab could bring these contaminants into solution for final testing. 2. Deterioration by Environmental Exposure - Acid Swab This is a phenomenon which occurs when a certain material suffers deterioration due to the presence of small concentrations of aggressive contaminants in the air. The surface

of the sample would end up covered with a film of the contaminant which can be removed by an acid swab for final testing. An area of cable will be swabbed using a filter paper soaked in 10% nitric acid. The filter paper will be then acid digested. The digest will be analyzed for metals using ICP. This is a slightly more aggressive approach than that in Scheme 1. 3. Corrosion Products - Inorganic Analysis If surface attack takes place on a prolonged basis, corrosion products may be present and visible on the surface of the sample. Corrosion products are will be scraped off, acid digested and analyzed for metals by ICP. 4. Degradation by Contact with Organic Compounds If the presence of organic contaminant compounds is found or suspected (tar, fossil fuels, solvents, lubricants, etc), the sheath(s) on the cable, this could lead to deterioration of the cable. It may be possible to gather the contaminant with an organic solvent for analysis in the laboratory by Gas Chromatography/Mass Spectroscopy (GC/MS). The appropriate solvent needs to be selected. Contact of the solvent with the contaminant on the cable sample (may require extended contact) will dissolve the contaminant in the solvent for subsequent analysis in the laboratory.

4200 Microscopic Material Analysis If initial examination of the cable samples leads to any other conclusion than the ones above, other testing techniques can be used to help with the research for the root cause of the tube deterioration. Task Series 5000 Report Writing 5100 Draft Report MHI shall complete the study and submit three duplicates of a preliminary report within 45 days of receiving the termination samples. LMD-CTA shall review the report and provide comments to MHI. MHI will review the comments and will revise the report and submit a final one version to SEC in three duplicates. 5200 Final Report MHI will review the comments supplied by SEC and will revise the report and submit a final version to SEC in three duplicates. Task Series 6000 Additional (Optional) Testing 6100 Calorimetry Measurements Should the visual inspection determine that there is evidence of extreme overheating, these measurements may be required. The Calorimetry Measurements will indicate the maximum temperature that the insulation has experienced and would provide a good indication if the cables

and terminations have been subjected to any overload condition. If samples taken from adjacent the connector were compared to samples taken away from the termination – this test could also indicate if the thermal issue is associated with the termination or the cable. MHI would have to have a third party run these tests. 6100 Thermal Cycling Depending upon the results of the Calorimetry Measurements, additional thermal cycling tests may be recommended. SEC and MHI engineers will examine the results and jointly decide if Thermal Cycling Testing will be conducted. The tests are conducted as per IEEE Std 48, which specifies the following cyclic aging test. 15 kV terminated cables are energized at 26 kV rms. 35 kV terminated cables are energized at 61 kV rms. The terminated cables are subjected to 30 thermal cycles. This is accomplished by circulating current in the cable to establish a maximum conductor temperature midway between the terminations of within 5oC of the cables maximum rated emergency operating temperature for 6 hours. When the current is off the temperature of the conductor must decline to within 5oC of ambient. This would take at least 20 days. Following the 30 thermal cycles the terminated cables are subjected to partial discharge measurements and lightning impulse tests. Same as for 3200 and 3400. Notes Regarding the MHI Test Plan Tests Not Recommended

MHI recommends that Item 2 in the Scope of Work be omitted. This test (calculation) is confirming the design of the cable termination stress cone. MHI feels that this is a proven design used on cables installed in thousands of locations, and should not be the source of the problem that SEC is experiencing.

MHI has not included any system studies in the test plan to determine if these cables

faults are due to extreme system overvoltage conditions. Since the cable lengths are relatively short (~ 70 metres according to SEC information), and since the faults are not centralized in a specific area, it is doubtful that the faults are caused by extreme system overvoltage conditions

No. Responsibility Resources Duration Level of Effort

(Department) (No. of Staff) (Days) (Man-Days)1000 Shipment of Cables / Termination Kits To Winnipeg 1 2

1100 Shipment of Cables To Winnipeg SEC SEC ???1200 Unpacking at Manitoba Hydro Testing Facility IET 2 1 2

2000 Preliminary Inspection and Contamination Testing 11 182100 ESDD / NSDD Testing of In-Service Cables

2110 Preparation IET 2 2 42120 Sampling / Testing IET 2 1 22130 Analysis of Results IET 1 2 2

2200 Hydrophobicity Tests IET 2 1 2

2300 Visual Inspection & Disection of Damaged Terminations All 4 1 4

2400 Microscopic Material AnalysisSet Up IET 1 1 1Analysis IET 1 3 3

3000 Electrical Tests (5 Cables) 25 413100 Cable Preparation U/G Distribution 1 3 3

3200 Partial Discharge TestsSet Up IET 2 1 2Testing IET 2 1 2Analysis IET 1 1 1

3300 HV Withstand TestSet Up IET 2 1 2Testing IET 2 1 2Analysis IET 1 1 1

3400 Lightning Impulse Test (University of Manitoba)Set Up IET / U of M 2 4 8Testing IET / U of M 2 4 8Analysis IET / U of M 2 2 4

3500 Resistance Tests

Description

Set Up U/G Distribution 1 1 1Testing U/G Distribution 1 1 1Analysis U/G Distribution 1 1 1

3600 Volt - Amp Test On Stress Control MaterialSet Up IET 2 1 2Testing IET 2 1 2Analysis IET 1 1 1

4000 Chemical Tests 7 94100 Contamination Analysis

Set Up Chemical Lab 1 1 1Testing Chemical Lab 2 2 4Analysis Chemical Lab 1 1 1

4200 Microscopic Material AnalysisSet Up Chemical Lab 1 1 1Testing Chemical Lab 1 1 1Analysis Chemical Lab 1 1 1

5000 Report Writing 13 18Cable Specialist Hamilton 1 4 4HV Testing Specialist McDermid / Swatek 2 5 10Chemical Specialist Carneiro 1 2 2MHI Project Manager Schumann 1 2 2

Total Duration 57Total Level of Effort 88

No. Responsibility Resources Duration Level of Effort

(Department) (No. of Staff) (Days) (Man-Days)6000 Optional Testing 35 52

6100 Calorimetry Measurements Outsourced

Description

6200 Cycling Aging TestSet Up IET 2 5 10Testing IET 1 15 15Analysis IET 1 2 2

3200 Partial Discharge TestsSet Up IET 2 1 2Testing IET 2 1 2Analysis IET 1 1 1

3400 Lightning Impulse Test (University of Manitoba)Set Up IET / U of M 2 4 8Testing IET / U of M 2 4 8Analysis IET / U of M 2 2 4

Task Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

1100 Shipment1200 Unpack

2100 ESDD / NSDD2200 Hydrophobicity2300 Visual & Disection2400 Micro Mat'l Analysis

3100 Cable Prep3200 PD Tests3300 HV Withstand3400 Lightning Impulse3500 Resistance3600 VA Test on Stress Cone

4100 Contamination4200 Micrscopic Material

5100 Draft Report 5200 Final Report

6100 Optional6200 Optional

Days

Task Series Cost Element Quantity Rate Cost FX Rate Rate Cost($CAD) ($CAD) 3.5 (SAR) (SAR)

1000 MHI Labour Days 2 $1,276 $2,552 4466 8932SEC Hotel Nights 4 $150 $600 525 2100SEC Per Diems 4 $100 $400 350 1400

Sub-Totals $3,552 12,432

2000 MHI Labour Days 18 $1,276 $22,968 4466 80388SEC Hotel Nights 24 $150 $3,600 525 12600SEC Per Diems 24 $100 $2,400 350 8400

Sub-Totals $28,968 104,888

3000 MHI Labour Days 41 $1,276 $52,316 4466 183106SEC Hotel Nights 56 $150 $8,400 525 29400SEC Per Diems 56 $100 $5,600 350 19600

Sub-Totals $66,316 232,106


Sub-Totals $11,484 40,194


Sub-Totals $22,968 80,388

Other Costs International Airfare 2 $10,000 $20,000 35000 70000Local Travel 1 $1,000 $1,000 3500 3500Reproduction 1 $500 $500 $1,750 1750

Sub-Totals $21,500 75,250

Total Cost $154,788 541,758

Cable Failure Test Plan

Flow Chart

فحص الكابلات

Education