Archive for the ‘DNO’ Category

Smart Grid – A Vision of the future

Wednesday, April 28th, 2010

Smart grid is the term applied to tomorrow’s electricity system. It encompasses a variety of changes that will transform the way electricity is used, delivered and produced, and result in a cleaner more efficient and more interactive electricity system. It represents a paradigm shift for electricity much in the way that mobile phones transformed communications. The concept is broad; it stretches beyond modernization of the transmission and distribution grid to include devices that allow consumers to better manage their electricity use, new ways of creating and storing electricity, and the widespread adoption of electric vehicles.

The power grid shift to move to a culture of conservation and its substantial commitment to renewable energy will also be supported by the smart grid. Smart meters, a major smart grid component, can give consumers timely information on price and consumption. Emerging devices will empower consumers to act on this information automatically while at the same time improving their energy efficiency, comfort and convenience. New sensing, monitoring, protection and control technologies will enhance the ability of the grid to incorporate renewable generation.The institutional structure of the electricity industry makes it easy to look at how the smart grid will impact each piece of the system in isolation, but the most profound impact of a smart grid may be its ability to link these pieces more closely together.

With the regulator OFGEM, we could have a system of applying structured market operator requirements with corporation responsibilities, encouraging longer-term system network planning, and procuring electricity supply and demand resources connected to the network. Both by the electrical shippers, National Grid and and the the regional Distribution Network Operators (DNO’s). but also the Feed in tariff (FIT’s) small generation customers and CHP and renewable end customer/suppliers. While the smart grid will affect each of these segments in different ways, it will affect all of them by increasing their ability to work together to better serve consumers.

Smart Grid Definition
A smart grid is a modern electric system. It uses communications, sensors, automation and computers to improve the flexibility, security, reliability, efficiency, and safety of the electricity system. It offers consumers increased choice by facilitating opportunities to control their electricity use and respond to electricity price changes by adjusting their consumption. A smart grid includes diverse and dispersed energy resources and accommodates electric vehicle charging. It facilitates connection and integrated operation. In short, it brings all elements of the electricity system – production, delivery and consumption closer together to improve overall system operation for the benefit of consumers and the environment. A smart grid is not only information rich, but also has the analytic infrastructure, processes and trained individuals necessary to integrate and act on information in the very short time frames required by the electricity system. It is characterized by clear standards, security protection and open architecture that allow for continued innovation through the development and deployment of new technologies and applications by multiple suppliers. So OFGEM must get it right, undertaking discussions with both the customer and the electrical supply and distribution network industry community.


Driver’s for a smart Grid

The Goverment’s commitment to establishing a culture of conservation and the desire to reduce the environmental footprint of the electricity sector are major drivers for creating a modern grid. The culture of conservation requires the continual search for new ways to encourage all customers to use energy more efficiently and lower consumption during peak periods. The comprehensive provision of smart meters creates the opportunity for all customers to better understand and manage their electricity usage and, for those who wish, to become active providers of demand response, and be rewarded in doing so.

The prominence of renewable energy in the Governments white papers an increased ability to accommodate variable renewable generation from off shore tidal, wind farms, solar, biomass and micro generation. Where today the grid serves primarily as a vehicle to move electricity generated in large central facilities to consumers, in the very near future, the grid will need to do much more. As the number and distribution of smaller generators grow, Micro generation (FITs) come on line, the operational challenge of incorporating these independent generated energy resources, while maintaining safety and reliability, will also grow. Meeting this challenge will require a smart grid. Other features of this arrangement will also also drive the development of a smart grid. DNO’s will need to upgrade, renew or replace a significant amount of the existing electricity infrastructure network load monitoring and reporting real time demand and quality of supply (similar in some ways to end customer smart meters to be rolled out) In addition dynamic load forecasting to request power stations load demand requirements. This need creates an opportunity to use smart grid technology both to maximize the use of existing equipment and to improve the efficiency of the grid as it is replaced. Growth and redevelopment also present opportunities to introduce smart grid technologies in newly developed and reconstructed areas. Demands by industry and consumers for increased reliability and power quality technology are also pushing toward a smarter grid.

Promise, Cost and Timing Of a Smart Grid
There are many potential benefits from a smart grid in the areas of economics, environment and operating performance. The ability of consumers to increasingly participate in the electricity market by adjusting their demand in response to price or other signals will help to defer the need for peaking resources and incorporate additional generation from variable sources. Improved system economics will come from reduced losses during electricity delivery (line losses) and better use of power station and distribution network plant & equipment. Potential reductions in network congestion will also allow greater use of the most cost effective generation and improve the capacity to move generation throughout the electrical supply network. Greater ability to integrate generation and load can also reduce the cost of operating reserve and some ancillary services. Finally, improved analytics and the ability for the grid to automatically restore itself from faults can reduce the scope and duration of outages, lower operations and maintenance costs, and improve service to customers. Many of the identified economic benefits also have associated environmental benefits. Reduced losses not only reduce cost, they allow more of the electricity generated to reach consumers thereby lowering the environmental impacts from generation. Increased ability to incorporate distributed energy resources, including both renewable generation and demand response, will allow us to move more quickly to a cleaner resource mix that everyone generally wishes to be collectively archive. Even if if it is viewed by some, that this is achieved by someone else. Using existing assets more efficiently can defer the need to expand the grid to accommodate growth. The smart grid offers enhanced operational performance. Greater awareness of system conditions can help anticipate and address problems before they lead to outages, minimize the scope of outages that do occur, and enable more rapid restoration of power. With a smart grid, these fixes may increasingly occur automatically so that the grid becomes self healing.

The ability to remotely monitor equipment condition and performance can also enhance security, help better target maintenance and improve the accuracy of replacement decisions. The information provided by a smart grid also can be used to improve power quality, which is increasingly important in operating today’s sophisticated equipment controlled by digital electronics.

By automating functions that are controlled manually today, the smart grid will increase productivity, which will be essential in managing the more complex grid of tomorrow and helpful in addressing the demographic issues facing the electric system as the baby boomer’s retire and new workers need to be hired and trained. Finally, the smart grid can provide significant operational advantages through its ability to improve both public and worker safety by increasing the amount of system information available for protection and control and by enabling remote operation and automation of equipment. The costs of the smart grid are difficult to quantify. They will depend on investment decisions and the pace of implementation by numerous companies and individuals undertaking smart grid expenditures. It is through the analysis underlying these decisions that the benefits and costs of specific smart grid investments will be evaluated. Certain cost elements that support the smart grid have already been incurred. Ontario’s investment in smart meters and advanced metering infrastructure provide an important connection with customers and the beginning of the communications infrastructure necessary for a smart grid. Additional communications, with greater bandwidth, speed and reliability will be needed, for full smart grid implementation. Moreover, much of the distribution infrastructure replaced over the last few years is already smart grid compatible.

Customer support also would be a key factor in evaluating smart grid investment and customer education will be necessary to inform consumers on this issue. Investment at this level would require increased availability of demonstrated smart grid technology and the human resources to install and integrate it. Finally, the costs and benefits of proposed incremental smart grid investments would be evaluated through appropriate regulatory processes. The timing of smart grid development also will depend on individual investment decisions, which in turn will be influenced by external policy drivers. The investment plans by Electrical shippers, distribution network operators, IDNO’s, meter operators and consumers that will largely determine the pace of adoption for smart grid technologies will be based on their individual needs and circumstances, and their available capital. Government policy, implemented through incentives, mandates or regulatory initiatives will be a major factor in influencing the timing of investments. In short, because the smart grid is not a single project, but rather a series of actions by a variety of entities to modernize the electricity system, it is difficult to produce a definitive time line for smart grid development.

When it does come together, and matures, the system as a ‘whole’, will be more resilient, but it will dependable on all parties being dependable on each other. Including the micro generation and independent supply generation supply contribution and working efficiently, otherwise extra power stations will still be required to be built or available, just in case all independent customers disconnect supplies from the network, say as a future government protest action, interrupting the collective electrical supply contribution factored in the ultimate smart generation mesh smart grid arrangement.

In some respectsit is similar to the how the internet developed and matured and came to be more resilient and depended by everyone including the internet backbone and local ISP’s provide the network grid to connect people and systems together.

Another interesting development will be how supply authorities & DNO’s will undertake works on the network.

For the purposes of this blog, assume in simplistic traditionally engineering supply arrangements, that electricity is generated from a remote power station, distribution via the national grid 132KV network to the local DNO network (66 / 33 /11 / 6.6KV substation network to a 230 V rated supply and so onwards the the end customer via the service cutout consumption monitored by the electrical meter / CT arrangement . Generally, electrical only going one way – Power station via DNO’s to the end customer.

So isolation of cabling & equipment only required from local substation supply to be dead supply to enable major upgrade work to be undertaken.

In comes the Smart grid roll out which end customers are encouraged to provide their own renewable energy, with spare capacity connected and used by local network So introducing multiple back-feed supply’s. Always connected, but independently controlled and managed by the customer, supply on and off all the time – generally individually, each micro generation arrangement not resulting a constant dependable supply contribution, only achieved collectively when provided in clusters of connection points.

So back to the final distribution feeder cable supply requiring major works to be undertaken. DNO isolates at substation and is checked and tested that the LV cable was a ‘dead’ cable, but it could become live at any time, thanks to customers micro-generation connected supply.

So how do you isolate the DNO feeder cable, to cut or repair the cable?

OK – Live working methods can be used and will have to be adopted through the LV network from now on.

But the customers generation equipment will also have to be able to provide circuit protective devices from a grid network earth fault or the remote chance that the distribution point may not be connected to the network. But thats a separate subject, as well!

In a joint up world – simple things get complicated – but systems change and adapt to “keep it simple” – to make it more easier to manage and control.

Agreement to use DNO’s circuit breaker to protect User’s network

Friday, April 9th, 2010

Preamble
The agreement to allow the use of the DNO’s CB and/or the DNO’s protection relays and systems to protect the User’s network is based on reasonable endeavours by the DNO to accommodate the User’s needs. The agreement can be terminated by either party at any time. The DNO reserves the right to terminate the agreement should alterations to his network preclude the continued delivery of these services.

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The DNO will use reasonable endeavours to find new solutions for continuing to provide the services, but any costs will be charged on a T&M basis to the User.

Cost indicated as x, y, a, b, c, d, e, f would be specified individually by DNOs, possibly in accordance with a revised LC4 statement.

Tripping
The DNO’s CB can be tripped by the User’s protection; on request from the User’s Control Person; or by the User directly via an emergency trip button. There will be no charge for these operations.

Closing
The DNO’s CB will not be used for synchronizing.

The DNO’s CB cannot be closed by the User. Should the User wish the DNO to energize the User’s system, this will be requested in the normal manner by the User’s Control Person.

There will be no charge for the first [] operational closes to energize the User’s system in any financial year. Subsequent closes will be charged at £[x] for closes by telecontrol and £[y] for closes by the DNO’s staff on site.

The DNO and the User may agree to implement an automatic reclosing system for the DNO’s CB. There will generally be no charges for operation of the CB under this system.

Exceptional Maintenance Costs
Any exceptional maintenance costs, such as post-fault maintenance of the DNO CB following the clearance of a fault on the User’s system, will be charged to the User on a T&M basis at £[z] per hour.

Isolation and Earthing
The DNO will provide an isolation and earthing service for the User’s network.

The DNO will attend to effect isolation and or earthing with [] days notice. The charge per attendance will be £[a] for the first hour or part thereof and £[b] for each subsequent hour or part therof.

For an unplanned event, the DNO will endeavour to attend within three hours. During exceptional event periods reasonable endeavours will apply. Attendance for unplanned events will be charged at £[c] per hour during the period 0830 to 1700 Monday to Friday, and £[d] at all other times.

Testing
The DNO will provide services for isolation and earthing as above for the purposes of facilitating the User’s need to test his circuits.

User’s Protection
The User’s Protection can trip the DNO’s CB.

The DNO and the User will agree as to the provision of DC supplies for the User’s protection. Where the DNO provides the DC supplies, the cost of the DC supplies will be shared on an equitable basis.

The User will be solely responsible for monitoring the health of the User’s trip circuit, including any parts of the circuit afforded by DNO equipment.

Co-ordination of Protection
In accordance with DPC4.4.4 the DNO and the User will agree the protection co-ordination arrangements, including specific faults on the User’s system that the DNOs protection will be relied upon to clear. The User will furnish the DNO with a schedule of these specific faults. The User will state for each specific fault if the DNO is required to ensure that the fault will also be protected by the DNO’s back up protection should the DNO’s interface CB fail to trip for any reason. The DNO shall describe the protection systems (including any backup systems) and the settings to be applied and the user shall then make an assessment as to whether the protection provided by the DNO equipment is adequate to meet their statutory obligations and commercial requirements The DNO will charge £[e] for each such protection assessment.

Limitation of DNO’s Liability
The DNO shall [have no liability/agree the liability] to the User for the failure of the DNOs CB, and/or backup protection and/or backup CB, to operate correctly to clear a fault on the User’s system.

The DNO shall [have no liability/agree the liability] for the failure of any DC supplies afforded by the DNO for the purpose of operating the User’s protection.

The DNO shall provide such information about the design, condition and operating characteristics of the DNO’s protection and CB as the User may from time to time request. This information will be collated by the DNO on a T&M basis at a charge of £[f] per hour. The DNO will provide an indicative estimate of the number of hours to collate the information on request

What type of elecrical customer are you?

Friday, April 9th, 2010

CATEGORIES OF USERS OF THE DISTRIBUTION SYSTEM

Category AUsers are those having a connection at 1 kV or above (HV)

A1. Embedded Generators including CWOGs having an output capacity of 1 MW and above.

A2. Embedded Generators including CWOGs having an output capacity of less than 1 MW.

A3. Customers without generation having a Demand of 5 MW and above.

A4. Customers without generation having a Demand of less than 5 MW.

The classification threshold of 5 MW is related to the obligations that a DNO has for providing aggregated Demand information to NGC. Generators are further classified by voltage of connection and capacity for the purposes of technical standards.

Category B – Users are those having a connection at below 1 kV (Low Voltage)

B1. Embedded Generators (including CWOGs) irrespective of capacity of fuse(s) or other Protection device(s).

B2. Customers who are the sole Customer with a connection to the Low Voltage side of a High Voltage to Low Voltage transformer, irrespective of the capacity of fuse(s) or other protection device(s).

B3. Customers without generation and having a single or three phase supply protected by fuse(s) or other device(s) rated at more than 100 amps.

B4. Customers without generation having a single phase or three phase supply protected by a fuse(s) or other device(s) rated at 100 amps or less.

B5. Customers with Unmetered Supplies.

B6. Customers who have connected a Generation Set in accordance with ER G83/1-1 and where this is their only Generation Set.

C. Suppliers including licence exempt Suppliers, unless otherwise stated.

D. Other Authorised Distributors connected to the DNO’s Distribution System, being licensed or licence exempt Distributors.

E. Meter Operators (This Distribution Code does not place any direct obligation on Meter Operators other than through the appointment by either a Supplier or a Customer.)

Embedded Generator

Friday, April 9th, 2010

As defined under The Distribution Code of Licensed Distribution Network Operators (UK):

A Generator including a Customer With Own Generation whose Generation Sets are directly connected to the DNO’s Distribution System or to an Other Authorised Distributor connected to the DNO’s Distribution System.
The definition of Embedded Generator also includes the OTSO in relation to any Embedded Transmission System

Detailed Planning Data (DPD)

Thursday, April 8th, 2010

As defined under The Distribution Code of Licensed Distribution Network Operators (UK):

Detailed additional data which the DNO requires under the Distribution Planning and Connection Code in support of Standard Planning Data.

Definition: DNO’s Distribution System

Thursday, April 8th, 2010

As defined under The Distribution Code of Licensed Distribution Network Operators (UK):

The System consisting (wholly or mainly) of electric lines owned or operated by the DNO and used for the distribution of electricity between the Grid Supply Points or Generation Sets or other Entry Points to the points of delivery to
Customers or Authorised Electricity Operators, or any Transmission Licensee within Great Britain and Offshore in its capacity as operator of the licensee’s Transmission System or the National Electricity Transmission System and includes any Remote Transmission Assets (owned by a Transmission Licensee within Great Britain), operated by the DNO and any electrical plant and meters and metering equipment owned or operated by the DNO in connection with the distribution of electricity, but shall not include any part of the National Electricity Transmission System

Definition: Authorised Electricity Operator (AEO)

Thursday, April 8th, 2010

As defined under The Distribution Code of Licensed Distribution Network Operators (UK):

Any person (other than the DNO in its capacity as an operator of a Distribution System) who is authorised to generate, participate in the transmission of, distribute or supply electricity.

Definition: Connection Agreement

Thursday, April 8th, 2010

An agreement between the DNO and the User or any Customer setting out the terms relating to a connection with the DNO’s Distribution System (excluding any CUSC Bilateral Agreement).

TECHNICAL – Glossary & terms used for electrical supplies

Wednesday, May 20th, 2009

GLOSSARY
active power – the multiple of the components of alternating current and voltage that equate to true power. Normally measured in kilowatts (kW) or megawatts (MW).
adoption agreement – an agreement between a developer and a DNO, concerning the transfer into DNO ownership of infrastructure supplied and installed by a third party.
approved contractor – a contractor which has been approved by the DNO for carrying out third party connection work.
Balancing and Settlement Code (BSC) – the code which determines the rules governing the Balancing Mechanism and the settlement process for electricity trading in England and Wales as from time to time amended.
capacity factor – a factor, generally applied to renewable energy schemes, which relates the maximum continuous power output of the generator to the expected long run average power output.
committed network – future network configuration for which financial approval has been given.
condition 4 statement – document published by a DNO outlining the basis of charges for connection to the DNO’s distribution system.
connection agreement – an agreement setting out terms relating to a connection with the DNO Distribution System (excluding any bilateral agreement with the transmission licensee).
Connection and Use of System Code (CUSC) – contractual framework for connection to and use of the NGT transmission system.
connection voltage – voltage level at which a site is connected to the transmission or distribution system.
contestable – that part of the connection works which is open to competition.
CDM Regulations – the Construction (Design and Management) Regulations 1994.
Regulations specifying the duties of designers to minimise health and safety hazards involved in the construction of buildings and other installations.
CD&M Regulations – see CDM Regulations.
Declared Net Capacity (DNC) – declared net capacity: the maximum power available for export on a continuous basis minus any power imported by the station from the network to run its own plant.
determination (of disputes) – any dispute arising under certain sections of the Electricity Act 1989 between a DNO and a person requiring a supply of electricity, can be referred to Ofgem for determination. These determinations are then published as a matter of public record, and then form ‘case law’ on the subject.
distributed generator – a generator which is connected to a DNO’s distribution network rather than to the transmission grid. Distributed generation is generally a lot smaller than plant connected to the transmission grid as the maximum operating voltage of the distribution network is 132kV (and 33kV in Scotland).
Distribution Network Operator (DNO) – a holder of a Distribution Licence.
electronic inverter system – an electronic device placed between a generator and the network it is connected to for the conversion of power at one frequency to another (including dc/ac). The output voltage and frequency may be determined by the control equipment associated with the inverter or by the voltage and frequency of the
network it is connected to.
embedded generator – now generally termed distributed generator (see above), although this term is still used in the Distribution Code of Great Britain and the Grid Codes.
extension – It is sometimes necessary to extend the DNO’s distribution network in order to provide a connection for a new user or generator of electricity. Network extensions are often required for generation schemes in remote locations.
fault contribution – the contribution of an electrical source, such as a distributed generator, to the total fault levels in a distribution network.
high voltage (HV) – any voltage exceeding Low Voltage (ie exceeding 1000volts between phase conductors or exceeding 600volts between phase conductors and earth).
induction generator – a type of rotating electrical generator which operates at a speed not directly related to system frequency. The machine is generally excited by reactive power drawn from the network to which it is connected and the output voltage and frequency are determined by those of the network to which it is
connected.
islanding – islands of supply are discrete parts of a distribution system which are capable of generating and maintaining a stable supply of electricity to the customers within those discrete parts without any connections to the rest of the system.
line drop compensation – a voltage control scheme (used for the control of voltage levels in distribution networks) which compensates for the change in voltage drop in a long line as the current in the line changes.
loss of mains – the loss of an electrical connection between a section of a distribution network and the main grid supply, often due to the operation of circuit breakers.
low voltage (LV) – in relation to alternating current, a voltage exceeding 50 volts measured between phase conductors (or between phase conductors and earth), but not exceeding 1000volts measured between phase conductors (or 600volts if measured between phase conductors and earth).
Long Term Development Statement (LTDS) – (sometimes referred to as the LC25 statement). Statement prepared annually by each DNO as required by Standard Condition 25 of the Electricity Distribution Licence.
mains paralleling – the operation of an electrical generator while connected in parallel with the main grid supply.
negative reactance compounding – a voltage control scheme (used for the control of voltage levels in distribution networks) which allows the voltage–regulated system to be fed from two or more transformers in parallel.
Ofgem – the Office of Electricity & Gas Markets (under the Gas and Electricity Markets Authority, established by the Utilities Act 2000).
point of common coupling – the point in the distribution network where the lines or cables which are used solely to provide the supply to one customer (eg a generation scheme) are connected to infrastructure which is also used to provide supplies to other customers.
primary – generic term used by a DNO to indicate the source of the main 11kV or 6.6kV HV distribution network; eg primary substation – 33/11kV or 66/11kV transformation substation infeed to the 11kV network; 11kV primary busbar – source 11kV busbar for an 11kV network.
protection system – the provisions for detecting abnormal conditions in a system and initiating fault clearance or actuating signals or indications.
reactive power – the product of voltage and current and the sine of the phase angle between them which is normally measured in kilovar (kVAr) or megavar (MVAr).
reactor – wound network component generally used to limit reactive power flows and
hence fault levels.
reinforcement – Reinforcement work is usually required to increase the electrical capacity of those parts of the network which are affected by the introduction of new generation or demand. Other work might include upgrading the switchgear at a substation some distance from the proposed generation scheme, due to the increase in fault level caused by the connection of the generator.
Small Scale Embedded Generator (SSEG) – a source of electrical energy and all associated interface equipment, rated up to and including 16A per phase, single or multi phase 230/400V ac and designed to operate in parallel with a public low voltage distribution network.
Static Var Compensator (SVC) – equipment for injecting or absorbing reactive power (Vars) at the point of connection to assist in control of system voltage.
supplier – a person or company providing a supply of electricity. This could be the
local DNO, a second tier supplier or an exempt supplier.
synchronous generator – a type of rotating electrical generator which operates without slip and at a speed that is directly related to system frequency.
thermal rating – the current-carrying capacity of a cable, an overhead line or any other item of electrical infrastructure, which is determined by the heating effect arising from electrical losses.
third party connection – connection provided by a contractor other than the local DNO.
Use of System (UoS) – the use of a transmission or distribution network by a generator, a supplier, a customer or an interconnected party for the purposes of transporting electricity.