Technical Losses In Pea

TECHNICAL LOSSES of PEA DISTRIBUTION SYSTEM Provincial Electricity Authority Thailand 1

Provincial Electricity Authority

OUTLINES - OVERVIEWS OF PEA - PEA’S DISTRIBUTION NETWORK PROFILE - PEA’S LOSSES COMPUTATION & ACCOUNTING - PEA’S OVERALL TECHNICAL LOSSES MANAGEMENT PROGRAM - CONCLUSIONS

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Provincial Electricity Authority

OVERVIEWS OF PEA Provincial Electricity Authority (PEA) is a government enterprise under the Ministry of Interior. It was established under 1960 act by the Royal Decree executed on September 20,1960, then published in the Government Gazette on September 27,1960

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Provincial Electricity Authority

PEA Service Area The service area of the PEA is approximately 510,000 km2, accounting for 928 PEA’s sub - office scattered throughout the country, rendering service to their customers. The PEA has grouped its services area into 4 regions. 4

Provincial Electricity Authority

Chiang Mai Udon Thani Phitsanulok Lop Buri Ubon Rat. Nokhon Ratchasima Ayutthaya Nakhorn Prathom Chon Buri Petchaburi

Nakhon Sri Thammarat Yala

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Provincial Electricity Authority

DISTRIBUTION NETWORK PROFILE PEA classifies distribution voltage level into 3 levels : - High voltage level : 115, 69 kV - Medium voltage level : 22, 33 kV - Low voltage level : 400/230 V 6

Provincial Electricity Authority

STANDARDIZE Conductor size for MV (I) PEA use the various type of conductors for MV. The standards according to TIS and IEC.

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Provincial Electricity Authority

STANDARDIZE Conductor size for MV (II) Bare Conductor Current Ratings Cross section (mm2) 50 95 185

Current Rating (Amperes) 225 340 520

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Provincial Electricity Authority

STANDARDIZE Conductor size for MV (III) Partially Insulated Cable Current Ratings Cross section (mm2) 50 185

Current Rating (Amperes) 185 425

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Provincial Electricity Authority

STANDARDIZE Conductor size for MV (IV) Spaced Aerial Cable Current Ratings Cross section (mm2) 50 185

Current Rating (Amperes) 180 410

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Provincial Electricity Authority

STANDARDIZE Conductor size for MV (V) Underground Cable Current Ratings : 240 mm2 Total Circuit 1 2 3 4 5

Current Rating (Amperes) 400 337 298 272 251

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Provincial Electricity Authority

STANDARDIZE Conductor size for LV Aluminum Conductor Current Ratings Cross section (mm2) 35 50 95

Current Rating (Amperes) 152 194 295 12

Provincial Electricity Authority

PEA’s Substation Transformer (I) The substation transformers shall have ratings as follow :

Rated power output : 30/40/50 MVA and 15/20/25 MVA Rated primary voltage : 115 kV On load tapping voltage : +10% to -10% of 115 kV, 1.25% in each step. 13

Provincial Electricity Authority

PEA’s Substation HV/MV

No 1 2

Transformer (II)

Substation Transformer

Transformation Transformer voltage Rating 115/22-33 115/22-33

50 25 14

Provincial Electricity Authority

PEA’s Substation MV/LV

Transformer (II)

Substation Transformer

No

Transformation voltage

Transformer Rating (kVA)

Phase

1

22-33kV/400-230 V

3 phase

2

22-33kV/230 V

50, 100, 160, 250, 315, 400, 500 10, 20, 30

1 phase 15

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INSTALLATION STANDARD 22-33 kV Aerial Cable Feeder & Bare Conductor Feeder 16

Provincial Electricity Authority

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Provincial Electricity Authority

Meter Installation

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Provincial Electricity Authority

CAPACITOR (I)

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Provincial Electricity Authority

CAPACITOR (II)

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Provincial Electricity Authority

LOSSES COMPUTATION & ACCOUNTING

The methodology to calculate losses of PEA : Energy Losses = Energy Requirement - Energy Consumption Energy Purchased Energy Generated

Energy Sales Free of Charge

Percentage of Losses = Energy Losses x 100 Energy Requirement (% Losses)

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Provincial Electricity Authority

Methodology for Distribution Losses Computation (I) Key variable Symbol /unit A Imported energy through transmission main intake substation (kWh) B Imported energy from utility owned distributed generation (kWh) C Imported energy from utility nonowned distributed generation (kWh)

Actual reading Variable used in /Estimated losses computation Yes Actual reading Actual reading

Yes

Actual reading (included A)

Yes 22

Provincial Electricity Authority

Methodology for Distribution Losses Computation (II) Key variable Symbol /unit Total metered sales for all LV/MV D customers (kWh) Internally used energy E (kWh) HV tariff sales (kWh) F Free of charge (kWh) G

Actual reading Variable used in /Estimated losses computation Actual reading Yes Actual reading

Yes

Actual reading Actual reading & Estimated

Yes Yes 23

Provincial Electricity Authority

According to the variable in the table above, we can find the formula for the computation of distribution system losses as follow : Energy Losses (kWh) = Energy Requirement - Energy Consumption = (A+B+C) – (D+E+F+G)

Energy Losses (%) = 1- (D+E+F+G)/(A+B+C) x 100% 24

Provincial Electricity Authority

Metering locations and reading frequency Key variable Symbol Metering Manual Sync. Reading /unit location Reading or AMR reading freq. Imported energy through A HV side Manual Yes End of transmission main intake month substation (kWh) Imported energy from utility B HV side Manual Yes End of owned distributed generation month (kWh) Imported energy from utility C HV side Manual Yes End of non-owned distributed monthly generation (kWh) 25 Provincial Electricity Authority Remark : Sync. Reading : Auto reset meter

Key variable Manual Symbol Metering /unit location reading or AMR HV side Manual Total metered sales for all D LV/MV customers (kWh) E HV side Manual Internally used energy (kWh) F HV side Manual HV tariff sales (kWh) Free of charge (kWh)

G

LV side

Remark : Sync. Reading : Auto reset meter

Manual

Sync. reading Yes & No

Reading freq. 15th-4th & 25th-26th every month No 25th -26th every month Yes End of month No 25th -26th every month 26

Provincial Electricity Authority

MA,B,C, synch. meter class 0.2 or 0.5 Record : at 0.00 am., at the end of every month. EGAT

PEA

MF, synch. meter class 0.2 Record : at 0.00 am., at the end of every month.

Large Cust.

Internal MD2, meter class 0.5 energy >30 kW ME, meter class 0.5 used

Record : on 25th -26th of every month. 115 kV 22/33 kV

E

Record : on 25th -26th of every month.

MD1, synch. TOU meter Record : at 0.00 am., at the Cust. >1 MBaht Cust. end of every month. Large Cust.

MD4, meter class 0.1 Cust. Record : on 15th -24th of every month. 15th-18th :40% 18th-21th :30% 21th-24th :30%

30 kW < energy < 66 kVA

MD3, meter class 0.1 Record : on 25th -26th of every month.

22/33 kV 400/230 kV

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Provincial Electricity Authority

12 region offices of PEA report losses data to PEA head office every month, the billing system (meter reading) and software analysis are used.

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Provincial Electricity Authority

This is the technical losses data of year 2004. Energy Purchased (kWh)

A, C

77,921,878.372

Energy Generated (kWh)

B

41,875,384

Energy Sales (kWh)

D, E, F

73,124,233,648

Free of charge (kWh)

G

995,987,988

Losses (kWh)

-

3,843,532,120

Losses (%)

-

4.93 29

Provincial Electricity Authority

Energy Losses (kWh) = (A+B+C) – (D+E+F+G) Energy Losses (%)

= 1- (D+E+F+G)/(A+B+C) x 100%

Losses Evaluation in 2004 by formula is: Energy Losses (kWh) = (77,921,878,372 + 41,875,384) – (73,124,233,648 + 995,987,988) kWh = 3,843,532,120 kWh Energy Losses (%)

= 1- (D+E+F+G)/(A+B+C) x 100% = 1-(74,120,221,636/77,963,753,756) x 100% = 4.93%

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Provincial Electricity Authority

Historical MW Demand growth Year MW at distribution level % growth

2000 8,724

2001 9,456

2002 9,962

2003 2004 10,639 11,721

5.81

8.39

5.35

6.79

10.17

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Provincial Electricity Authority

Historical Distribution Losses Level (I) Fiscal year

2000

2001

2002

2003

2004

Energy Purchase & Energy Generate (MWh) Energy Sales (MWh) Free of Charge (MWh) Losses (MWh) Losses (%)

56,292

(Sept04) 60,414 64,340 70,228 58,404

52,370 665 3,257 5.79

56,482 60,239 65,497 54,608 643 758 867 757 3,492 3,715 3,864 3,039 5.78 5.77 5.50 5.20 32

Provincial Electricity Authority

Historical Distribution Losses Level (II)

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Provincial Electricity Authority

Historical Distribution Losses Level (III) Fiscal year

2000

2001

2002

2003

Distribution losses (%) HV network (cct-km) MV network (cct-km) LV network (cct-km) Total KVA of Distribution transformer (MVA)

5.79 3,809 243,824 338,494 37,511

5.78 4,625 244,618 344,449 37,668

5.77 5,286 252,614 354,659 38,465

5.50 6,079 260,714 368,477 37,401

2004

(Sept04) 5.20 6,600 265,901 388,830 42,052

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Provincial Electricity Authority

PEA’s Energy Forecast (I) YEAR 2005 2006 2007 2008 2009 2010 Energy requirement 83,528 90,814 98,455 106,148 114,263 123,066 (GWh)

Peak demand (MW)

12,615 13,685 14,806 15,947 17,151 18,451

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Provincial Electricity Authority

OVERALL TECHNICAL LOSSES MANAGEMENT PROGRAM (I) 1. System Planning Design The criteria of substation and distribution system of PEA are :

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Provincial Electricity Authority

Substation’s Criteria 1) Transformer capacity : 25 MVA or 50 MVA 2) Transformer max. loading capacity : - 56% of rating capacity for N-1 criteria - 75% of rating capacity for N-0 criteria 3) Breaker rating (IC) : - 31.5 kA for 115 kV - 25 kA for 22/33 kV

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Provincial Electricity Authority

MV (22/33 kV) Distribution’s Criteria (I) 1) Voltage drop at peak load : - 5% for normal condition - 10% for emergency condition 2) Line loading capacity: - 8 MVA for 22 kV system, no more than 18 km. - 12 MVA for 33 kV system, no more than 27 km. 3) Conductor size : 185 mm2 aluminum in main feeders

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Provincial Electricity Authority

4) Types of conductors : - Bare conductors for clear area, rural area. - Spaced aerial cable for cities, industrial area and

lines under 115 kV transmission lines. - Underground cable for in front of substation and environment protected area. 5) Adequacy for transferring load from nearby substation. 39

Provincial Electricity Authority

LV (400/230 V) Distribution’s Criteria 1) Voltage drop at peak load : - 5% for normal condition - 10% for emergency condition 2) Line loading capacity: - 80% of line, transformer, no more than 1 km 3) Conductor size : 95, 50, 35 mm2 aluminum 40

Provincial Electricity Authority

The Standard Power Factor (I) 1) Standard Power Factor of PEA-EGAT : - Power factor > 0.875 lagging at each delivery point (EGAT Substation) - Power factor < 0.875 lagging must pay for penalty about 5 baht/kVAR/month of the different kVAR between original and 0.875 power factor. 41

Provincial Electricity Authority

2) Standard of HV Capacitor Bank : - 5, 10, 20, 30 and 75 kVAR 3 phase LV capacitor. - Fixed 3x100 and 6x100 kVAR. - VAR control, time control of 15x100 kVAR switched capacitor. - Power factor control 7.2 MVAR indoor capacity bank (3steps x 2.4 MVAR) substation installation only. 42

Provincial Electricity Authority

3) Standard Power Factor of PEA Customer : - Only 30 kW up demand customer is responsible for keeping power factor not less than 0.85 lagging. - Power factor < 0.85 lagging, the customer must pay for penalty about 5 Baht/kVAR/month.

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Provincial Electricity Authority

OVERALL TECHNICAL LOSSES MANAGEMENT PROGRAM (II) 2. Equipment Design & Specifications The PEA’s listings of MV&LV conductors with technical parameters and transformers with load & no load losses and impedance are : 44

Provincial Electricity Authority

CONDUCTOR designs & specifications (I) R1 X1 R0 X0 Conductor Type (ohm/km) (ohm/km) (ohm/km) (ohm/km) 185A 0.1764 0.4091 0.4005 1.5989 185PIC 0.2107 0.4144 0.3554 1.6448 50SAC 0.8219 0.3395 1.1093 1.8975 185SAC 0.2107 0.2986 0.4462 1.8310 45

Provincial Electricity Authority

CONDUCTOR designs & specifications (II) Conductor Type 185A 185PIC 50SAC 185SAC

G1 (uS/km) 0 0 0 0

B1 (uS/km) 3.5320 3.6360 5.1220 5.9510

G0 (uS/km) 0 0 0 0

B0 (uS/km) 1.9370 1.3640 1.3950 1.5220 46

Provincial Electricity Authority

TRANSFORMER losses & impedance Transformer Rating

No Load Loss

Load Loss

30/40/50 15/20/25

Up to 25.5 Up to 15.0

Up to 150 Up to 100

(MVA)

(kW)

(kW)

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Provincial Electricity Authority

OVERALL TECHNICAL LOSSES MANAGEMENT PROGRAM (III) 3. System Operation & Maintenance -Loading monitoring program : *for HV - record at substation monthly. *for LV - record at distribution transformer yearly. 48

Provincial Electricity Authority

3. System Operation & Maintenance (cont.) - PEA uses on load tap change transformers (OLTC) to manage voltage profile at HV/MV substations. For MV/LV substation, we analyze load in each area and change the tap of transformers to the proper tap. 49

Provincial Electricity Authority

3. System Operation & Maintenance (cont.) -Feeder balancing program : Standard : unbalance current < 10% Monitoring Procedure : by reading incoming & outgoing feeder at substation every month and measured distribution transformer’s load once a year. 50

Provincial Electricity Authority

Load unbalance Improving : Unbalancing > 10% 1-phase branches& 1-phase transformers& 1-phase customer shall be reconnected to the proper phases

1-phase branches’ load > 150 kVA

Upgraded to 3-phase 51

Provincial Electricity Authority

3. System Operation & Maintenance (cont.) -Power factor correction :

Monitoring Procedure : Power factor at substation shall be checked from meter reading MW and MVAR

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Provincial Electricity Authority

Power Factor Improving :

- Find optimal capacitor location using computer software. - Check real current and power factor from meters in existing system. - Obtain the optimal location. - Install LV fixed capacitor at 100 kVA or more distribution transformer. (kVAR = 10% of transformer Rating) 53

Provincial Electricity Authority

OVERALL TECHNICAL LOSSES MANAGEMENT PROGRAM (IV) 4. Technical Losses Assessment Methodology

PEA uses computer software such as PSS/Adept to calculate distribution losses. This soft-ware needs Single line diagram that contains the database as follow : - Daily Load (MW) - Length of feeders - Power factor

- Type and characteristic of Distribution transformers - No. and type of customers

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Provincial Electricity Authority

OVERALL TECHNICAL LOSSES MANAGEMENT PROGRAM (V) 5. Overall technical losses optimization, issues and learning points

* MVAR program or capacitor placement program - The fix capacitors are installed in every feeders. The capacitor rated is about 10% of each feeder’s load. - The installation of switching capacitors depends on daily load curve.

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Provincial Electricity Authority

5. Overall technical losses optimization, issues and learning points (cont.) * Voltage profile improvement program PEA has installed SCADA system to monitor and manage the equipments in distribution systems and also control voltage in system by switching capacitor. But SCADA isn’t reach full efficiency now, we have to improve it to handle all function of program. 56

Provincial Electricity Authority

5. Overall technical losses optimization, issues and learning points (cont.) * Loading profile improvement program - For distribution transformers, we have to manage the existing transformers and install new transformers or change to high rated transformer for increasing load. - The load monitoring at substations are programmed monthly to manage load profile. - PEA has plan to reduce capacitor of transformers, If the transformers supply load less than 30% of rated.

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Provincial Electricity Authority

CONCLUSIONS

PEA’s realized that the meter reading error such as the overlap reading date is the function of loss analysis’s error so the 50,000 AMR meters was planed to install within year 2007. Year No . of AMR Ratio to Total Per Year Accumulate

2004

2005

5, 000 15 , 000 10 % 30 % 10 % 40 %

2006

2007

Total

15 , 000 30 % 70 %

15 , 000 30 % 100 %

50 , 000 100 % 100 %

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Provincial Electricity Authority

CONCLUSIONS (II) To improve the technical losses analysis, PEA has employed the consultant to : - research, specify and improve the methodology of losses analysis and forecast. - develop the software for capacitor installation. - distribution transformer criteria in distribution system. The pilot area of this project is the feeder in the central area.

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Provincial Electricity Authority

CONCLUSIONS (III) And the last, PEA set up the losses optimization committee. The staffs are from PEA head office and region office in order to manage and find the methodology to optimize losses.

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Provincial Electricity Authority

The losses evaluation of the central area in year 2004. HV system MV system LV system Power Transformer Distribution Transformer

0.27% 2.44% 4.34% 0.17% 2.37% 61

Provincial Electricity Authority

THANK YOU for your attention 62

Provincial Electricity Authority