Electricity Networks. Empowering your energy future. Tom Langstaff- Network Planning. 21 March 2018

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1 Electricity Networks Empowering your energy future Tom Langstaff- Network Planning 21 March 2018

2 What do you see? 21 March

3 Once you see networks they are hard to unseen! 21 March

4 How does electricity get to your home? 21 March 2018 Author, Department 4

5 Traditional network hierarchy How does electricity get to your home? Generators Produces electricity. Located near the energy source. Transmission Network Carries electricity long distances to major load centres >100km s Direction of power flow Sub-Transmission Network Carries electricity between townships or suburbs >10km s Distribution Network Carries electricity to consumers through streets >km s Homes/Office & factories Use electricity for lighting/heating & power appliances 5

6 Traditional network hierarchy How does electricity get to your home? Sub-Transmission Network Carries electricity between townships or suburbs >10km s Distribution Network Carries electricity to consumers through streets >km s AusNet Services Distribution Network -EDPR 6

7 A closer look at Generators How does electricity get to your home? Key Points 1. Generators produce electrical energy (Power in Watts (W)) 2. Generators are located close to fuel sources 3. Typically the generators are a long distance away from where customers use the generated power Loy Yang Power Station- Latrobe Valley

A closer look at Transmission Networks How does electricity get to your home? Key Points 1. Transfers generated power to large load centres and interconnects states 2.

8 A closer look at Transmission Networks How does electricity get to your home? Key Points 1. Transfers generated power to large load centres and interconnects states 2. Uses very high voltage levels (electrical pressure, unit is a Volt (V)) to ensure efficiency of power transfer 3. This high voltage and power means lines need to be supported high off the ground via tower lines. 4. The voltage levels are 500,000 V and 220,000 V Transmission tower line.

9 A closer look at Sub-transmission Networks How does electricity get to your home? Key Points 1. Takes power from the transmission network and spreads it out to townships and suburbs 2. Is at a lower voltage (66,000 V) and power and can be run on simpler lower cost pole lines 3. Is a interconnected network to enable high levels of reliability Transmission Network Townships Interconnection of a Sub-Transmission Network

10 A closer look at Distribution Networks How does electricity get to your home? Key Points 1. Takes power from the subtransmission network and spreads it out to through streets to residential and commercial areas. 2. Has a lower level of interconnection 3. Typical made up of many lines called distribution feeders that support different areas of townships typically around 3000 customers. Transmission Network Townships Distribution feeders radiating from the sub-transmission network

11 A closer look at Customers How does electricity get to your home? Key Points 1. Most customers take supply at low voltage 240 V that comes out of the wall socket. 2. This lower voltage is achieved through a distribution transformer that takes the feeder voltage down from 22,000 V to 240 V. 3. There are hundreds of distribution transformers per distribution feeder Transmission Network Townships Connection of a customer to the distribution network

12 A closer look at Customers How does electricity get to your home? Distribution Transformer Distribution Feeder Service cable 240 V Transmission Network Townships Connection of a customer to the distribution network

13 Transitioning between networks Terminal Stations Zone Substations 21 March 2018 Author, Department 13

14 A closer look at Terminal Stations How does electricity get to your home? Key Points 1. Enables transition from transmission to sub-transmission networks 2. Enables power to be split into more lines at a lower voltage typically 220,000 V down to 66,000 volts 3. 66,000 V can be operated on a simple pole structure to traverse efficiently between townships and suburbs 4. Terminal stations are the key centres for which protection and control of the network can be undertaken

15 A closer look at Terminal Stations How does electricity get to your home? Sub-transmission pole lines heading out to communities Transmission tower lines heading in Terminal Station Showing transition from Transmission tower lines to subtransmission pole lines

16 A closer look at Zone Substations How does electricity get to your home? Key Points 1. Enables transition from sub transmission to distribution networks 2. Enables power to be split into more lines at a lower voltage typically 66,000 V down to 22,000 volts 3. Zone substations are the key centres for which protection and control of the network can be undertaken for the townships

17 A closer look at Zone Sub Stations How does electricity get to your home? Sub-transmisson lines arriving at the Zone Substation from Terminal station Typical Zone Substation Supplying a rural township Transmission tower line.

18 Key components at Stations- Transformers How does electricity get to your home? To enable transition from one network to another safely and efficiently the following key components are used; Transformers These make use of electromagnetic induction to lower the voltage from one side of the transformer to the other. Turns Ratio 3:1 66,000 V 22,000 V Magnetic Core Power in = Power out 21 March

19 Transformers can look different But all perform the same basic function! 21 March 2018 Author, Department 19

20 Key components at Stations- Circuit Breakers How does electricity get to your home? To enable transition from one network to another safely and efficiently the following key components are used; Circuit Breakers These interrupt power flow in case of a network issue and are an important part of the safety of the network. 21 March

21 Circuit breakers come in all shapes and sizes 21 March 2018 Author, Department 21

22 The rise of the bi-directional network An overview of a modern network The rise of decentralised generation challenges the traditional network hierarchy. Power can now flow in both directions due to embedded generation 21 March

23 Thanks for your time

24 Appendix Supporting information 21 March

Generation in Victoria Source: https://www.aemo.com.

25 Generation in Victoria Source: Status Coal CCGT OCGT Gas other Solar* Wind Water Biomass Other Total Existing Announced Withdraw al Existing less Announced Withdraw al Committed Proposed Withdraw n March 2018 Tom Langstaff, Networks Planning 25

26 Electricity 101 In a single graphic Voltage = Volt (V) Electrical pressure Current (I)= Amp (A) Flow of energy Resistance (R) = Ohm (Ω) - Limits the flow of current These three parameters relationship are summarised in the formula V=IR Tom Langstaff, Networks Planning V=IR Ohms Law 26

27 National Electricity Market (NEM) Australia s Electricity Network Operates on one of the world s longest interconnected power systems The NEM commenced operation as a wholesale spot market for electricity in December 1998 Spans Australia s eastern and south-eastern coasts and comprises five interconnected states that also act as price regions: Queensland New South Wales (including the Australian Capital Territory) South Australia Victoria Tasmania 40,000km of transmission lines and cables 9 million customers Supplies 200 terawatt hours per year $16.6 billion traded in the NEM FY Has a total electricity generating capacity almost 52,500 MW (April 2017) 27

National Electricity Market (NEM) Australia s Electricity Network The NEM is a wholesale electricity market in which generators sell electricity and retailers buy it to on-sell to consumers.

28 National Electricity Market (NEM) Australia s Electricity Network The NEM is a wholesale electricity market in which generators sell electricity and retailers buy it to on-sell to consumers. There are over 100 generators and retailers participating in the market, so it s highly competitive and therefore an efficient way of maintaining relatively competitive electricity prices in the wholesale market. Electricity production is matched to electricity consumption, and spare generating capacity is always kept in reserve in case it s needed. The current energy price can then be calculated. Electricity production is also subject to transmission limitations so that the network is not overloaded. 28

National Electricity Market (NEM) How the NEM Works The NEM, Grid & Financial Market work together The Financial Market Involves retailers and generators entering into hedging contracts to buy and

29 National Electricity Market (NEM) How the NEM Works The NEM, Grid & Financial Market work together The Financial Market Involves retailers and generators entering into hedging contracts to buy and sell electricity. These contracts set an agreed price for the electricity The Grid The transmission & distribution networks deliver electricity from power stations anywhere in the system to homes and businesses 24/7 29

National Electricity Market (NEM) Spot Market Electricity cannot be stored easily, so the electricity market works as a pool, or spot market, where power supply and demand is matched instantaneously

30 National Electricity Market (NEM) Spot Market Electricity cannot be stored easily, so the electricity market works as a pool, or spot market, where power supply and demand is matched instantaneously in real time through a centrally coordinated dispatch process. Generators offer to supply the market with specified amounts of electricity at specified prices for set time periods, and can re-submit the offered amounts at any time. From all the bids offered, the Australian Energy Market Operator (AEMO) decides which generators will be deployed to produce electricity, with the cheapest generator put into operation first. NEM operation is designed to meet electricity demand in the most costefficient way. 30

31 National Electricity Market (NEM) Fluctuating Prices All electricity sales are traded through the NEM. It is a wholesale market and prices fluctuate in response to supply and demand at any point in time. NEM MARKET PRICE The price of electricity in the NEM is based on: Offers by generators to supply electricity to the market at particular volumes and prices at set times. Demand at any given time. FINANCIAL MARKET PRICE To manage price volatility, retailers and generators often enter into hedging contracts to fix the price for future electricity sales. 31

32 AusNet Services AusNet Service Networks 21 March

33 AusNet Services Unique Characteristics of Our Distribution Network Key statistics: 80,000 km 2 service area 38,477km overhead 6,169km underground lines 380,000 poles 670,000 premises supplied Approx network faults per annum 22,000V powerlines AusNet Service customer base is more heavily weighted towards residential than any other Victorian distributor 33

34 Electricity Water Analogy Electricity can be understood using a water analogy Voltage = water pressure Current = water flow Resistance = flow limiting device (pool filter, narrow pipe) 34

Electricity Electrical Engineer in 2 Equations V=IR (Ohm s Law) Voltage (Volts-V)= Current (Amps-A) x Resistance (Ohms-Ω) 230 V = 0.

35 Electricity Electrical Engineer in 2 Equations V=IR (Ohm s Law) Voltage (Volts-V)= Current (Amps-A) x Resistance (Ohms-Ω) 230 V = A x Resistance Resistance = 8,840 Ω P=IV (Power Equation) Power (Watts-W) = Current x Voltage 6 W = Current x 230 V Current = A 35

36 Power Loss Electricity Losses High Voltage is dangerous, why do we utilise it? Answer: Losses Losses are most commonly in the form of heat and are wasted power About 5% of power is lost on AusNet Services network These losses are paid for in your electricity bill through loss factors (DLFs) P=IV where V=IR => P = I 2 R Current => Losses Reduce current to reduce losses Current 36

37 Electricity Transformation Transform the current down to send long distances, then transform voltage down to make it safer in communities. P=IV Same Power = Current x Voltage P in = P out V in I in = V out I out 220 x 2.27 = 66 x x 7.58 = 22 x 22.7 V = 500 kv I = 1 A Terminal Station V = 220 kv Terminal V = 66 kv Zone V = 22 kv Distribution V = kv I = 2.27 A Station I = 7.58 A Substation I = 22.7 A Substation I = 1205 A 37

38 Electricity Alternating Current Alternating Current oscillates backward and forward In Australia, the frequency is 50 Hz (or 50 times a second. One cycle is 20 ms Engineers prefer to think of sine waves in terms of phasors (or vectors) Benefits of Alternating Current over Direct Current Cheaper and Easier to make Easier to transform 38

39 Electricity 3 Phase Power Three voltages and currents 120 out of phase P= 3 VI Benefits of 3 phase More consistent power delivery No need for return path i.e. all active wires in air Delivers more power More efficient to generate R VRE=VRN VWE=VWN W N=E VBE=VBN B 39

40 National Electricity Market (NEM) Frequency Control Ancillary Services (FCAS) FCAS are used by AEMO to maintain the frequency on the electrical system at 50Hz GIF shows the continual movement & change that occurs between generation, demand & frequency 40

41 National Electricity Market (NEM) Frequency Control Ancillary Services (FCAS) Too much demand without enough generation, and the frequency will fall. Too much generation for the given demand and frequency will rise. If the frequency falls outside the 47-52Hz range, the power system will begin to collapse to protect the equipment and we will have blackouts as occurred in South Australia in September When all regions are synchronously connected, FCAS can be sourced from any region to meet NEM-wide requirements. No SA generating units were participating in the FCAS market prior to the event. Therefore the frequency in SA did not enter bands where FCAS response would have been triggered until after loss of the Heywood Interconnector. 41

Becoming complex Capacitance and Inductance Capacitance is the ability of a body to store an electric charge (i.e. like a battery) Power is stored and not used Creates a +90 phase shift in current

42 Becoming complex Capacitance and Inductance Capacitance is the ability of a body to store an electric charge (i.e. like a battery) Power is stored and not used Creates a +90 phase shift in current Boosts the voltage Its opposite is inductance Inductance is the property of the coil of inducing Electromagnetic Field due to the changing flux Power is also not used Creates a -90 phase shift in current Networks are usually more inductive in Australia. 21 March

Becoming complex Real and Imaginary Power and Power Factor Real power (Active Power) is the power that is used i.e. resistive loads Imaginary power (Reactive Power) is not used but takes up space S =

43 Becoming complex Real and Imaginary Power and Power Factor Real power (Active Power) is the power that is used i.e. resistive loads Imaginary power (Reactive Power) is not used but takes up space S = P + jq Apparent Power, S, is measure in Volt-Amps (VA) Real Power, P, is measured in Watts (W) Reactive Power, Q, is measured in volt-amps reactive (var) Aim to deliver real power as reactive is a waste of space Power factor is a measure of how real is the power. PF = P (W) / S (VA) Networks are usually more inductive in Australia. We add capacitance to offset this inductance 21 March

44 Reliability Network and Asset Core requirement of our customers is that power should be there at the flick of a switch Reliability is a term describing how frequently the lights stay on It is measured in its opposite of how frequently the lights go off and for how long Network Reliability is focused on events such as car into pole, animal and bird, vegetation, and weather Asset Reliability is focused on the condition of the asset and its likelihood of failure 44

45 Reliability Network Network Reliability is usually studied using historical trend analysis Network Reliability is improved by programs such as: Animal proofing Vegetation clearing Lightning protection Sectionalising (limiting the outage area) 45

46 Reliability Network Double up! 46

47 Reliability Network Create Loops! 47

48 Reliability Asset Asset Reliability is usually studied using historical trend analysis along with condition assessments The goal is to replace the asset just before it fails Asset Reliability is maintained by projects and programs such as: Asset Replacement (risk based) Sectionalising (limiting the outage area) 48

Assets Asset Types Asset Types Primary The physical network Asset Secondary The protection Systems to detect leak and issue commands to turn the tap

49 Assets Asset Types Asset Types Primary The physical network Asset Secondary The protection Systems to detect leak and issue commands to turn the tap off Communications (comms) Allow the devices to tell to the centralised control room of their status and receive remote commands. Secondary device 49

Primary Assets Circuit Breakers 66 kv Bulk Oil CB

the water analogy CB failure modes can be grouped

50 Primary Assets Circuit Breakers 66 kv Bulk Oil CB 22 kv Vacuum CB 22 kv Indoor Vacuum CB The tap in the water analogy CB failure modes can be grouped into generic themes such as failure to: Failure to operate (e.g. due to corrosion), mechanical malfunction, loss of internal liquids or gasses (e.g. oil leaks) 50

are: Insulation degradation, Partial discharge and puncture between foils, Oil leaks

51 Primary Assets Instrument Transformers 66 kv CT s 66 kv MVT Measurement devices in water analogy and in electricity Common failure modes for instrument transformers are: Insulation degradation, Partial discharge and puncture between foils, Oil leaks from porcelain/steel interfaces, Rust on containing tanks, Surface pollution on insulators 51

Primary Assets Surge Arresters/Lightning Arresters/Surge Diverters

intentionally fails upon lightning so all power flows through them

Voltage / impedance characteristics deteriorate, Corrosion or

52 Primary Assets Surge Arresters/Lightning Arresters/Surge Diverters Lightning Protection Normally no power flows through them, but it intentionally fails upon lightning so all power flows through them Surge arresters generally reach the end of their life when: Voltage / impedance characteristics deteriorate, Corrosion or deterioration of seals allows moisture to enter the inside of the arrester 52

53 Primary Assets Automatic Circuit Reclosers The tap in the water analogy like Circuit Breakers They can detect the leak (or fault) on its own The ACRs are reliable and we have been replacing them because they are obsolete (like an iphone 3) rather than they fail. 22 kv Noja ACR 53

54 Primary Assets Pole Assets 54

55 Primary Assets Other pole-top assets Mixed Assets 55

56 Projects Replacement Expenditure (Repex) Replacement is assessed based on risk cost versus project cost The goal is to replace the asset at the time the risk exceeds the cost Economic Assessment Annualised Capital Cost (Cost of the project over the life of the project) Risk = Failure Rate x Likelihood of Consequence x Cost of Consequence x duration (where applicable) Disproportionality factor sometimes taken into consideration 56

57 ($'000) Projects Augmentation Expenditure (Augex) N-1 and Energy at risk The goal is to augment the network at the time the cost exceeds the risk Economic Assessment Annualised Capital Cost (Cost of the project over the life of the project) Risk = Energy at Risk (POE) x Probability of Unavailability x Value of Customer Reliability $1,200 Sensitivity Study: VCR $1,000 $800 $600 $400 $200 $0 Annual Capital Cost Base Case 75% of VCR 125% of VCR 57

58 Boundaries Rules and Codes Many rules define how we operate our network and provide guarantees of quality of supply for the customer. Most significantly: National Electricity Rules Victorian Electricity Distribution Code Victorian Electricity System Code 58

59 Links March 2018 Author, Department 59

60 More Photos 21 March 2018 Author, Department 60

Introducing AusNet Services Regulated Energy Services and the Distribution Business

Introducing AusNet Services Regulated Energy Services and the Distribution Business March 2018 Presentation purpose The purpose of this presentation is to provide information on the following key topics: