Connection of micro-generation to the electricity distribution network

Network recommendation YA9:09 Connection of micro-generation to the electricity distribution network

Connection of micro-generation to the electricity distribution network Network recommendation YA9:09

ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 1(20)

Network recommendation YA9:09 Connection of micro-generation to the electricity distribution network

CONTENTS INTRODUCTION...........................................................................................................................3 1. MARKINGS AND DEFINITIONS ............................................................................................3 2. DEFINITION OF MICRO-GENERATION AND RESTRICTION ON SINGLE-PHASE PRODUCTION ...............................................................................................................................3 2.1. Definition of micro-generation.................................................................................................4 2.2. Restriction of single-phase generation .....................................................................................4 2.3. Quantity of micro-generation in the place of use.....................................................................4 3. DISCONNECTION OF THE INSTALLATION AND OCCUPATIONAL SAFETY IN THE NETWORK.....................................................................................................................................5 3.1. Disconnection of the installation and safe working in the electricity network ........................5 3.2. Taking account of the rear feed risk.........................................................................................6 3.3. Marking of micro-generation sites ...........................................................................................6 4. QUALITY OF ELECTRICITY FED BY THE INSTALLATION ............................................7 4.1. EMC requirements ...................................................................................................................7 4.2. Quality of electricity.................................................................................................................7 5. NETWORK CONNECTION OF THE INSTALLATION AND TRIPPING IN NETWORK FAULT SITUATIONS ...................................................................................................................8 5.1. Protection properties of the generation installation..................................................................8 5.2. The set values and operating times of parameters....................................................................8 5.3. Synchronisation with the network............................................................................................9 5.4. Loss of Mains protection........................................................................................................10 5.5. High-speed autoreclosers .......................................................................................................10 5.6 Use of reserve power...............................................................................................................11 6. SHORT-CIRCUIT CURRENTS FED INTO THE NETWORK BY THE INSTALLATION 11 6.1. Fault trip .................................................................................................................................12 6.2. Fault in protection ..................................................................................................................12 7. SITES WITH NO BUYERS FOR ELECTRICITY..................................................................13 8. METERING OF MICRO-GENERATION...............................................................................14 8.1. Sites with no electricity sold on the market ...........................................................................14 8.2. Sites with a maximum of 3x63 A with electricity sold on the market ...................................14 8.3. Sites of over 3x63 A with electricity sold on the market .......................................................15 8.4. On meter properties ................................................................................................................15 8.5. Registration and transmission of metering data .....................................................................15 9. CONTRACTS ON GENERATION..........................................................................................16 9.1. Technical information on the micro-generation equipment to be notified to the network company ........................................................................................................................................16 9.2. Sites not selling to the market ................................................................................................17 10. PRICING PRINCIPLES .........................................................................................................18 10.1. Connection fee......................................................................................................................18 10.2. Amount of connection fee when the site’s consumption is greater than its generation .......19 10.3. Amount of connection fee when the site’s consumption is smaller than its generation ......19 10.4. Network service fee..............................................................................................................19 10.5. Metering costs ......................................................................................................................19

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Network recommendation YA9:09 Connection of micro-generation to the electricity distribution network

INTRODUCTION There has been growing interest in distributed, local electricity generation along with the EU targets on the climate and increasing the use of renewable energy, lower prices of small-scale energy production plants, consumers’ interest in lowering their energy bills, and environmental awareness that is having an increasing impact on consumption decisions. It is the system operator’s task to offer a reliable network for electricity generation and to guarantee the operation and safety of electricity distribution even after connection to the grid. The purpose of this network recommendation is to facilitate the connection process of micro-generation for all parties concerned. This recommendation includes the technical requirements of connection, and it also provides information about the necessary contracts, metering, division of costs and entry to the micro-generation market. It only focuses on very small-scale generation, so-called micro-generation. The recommendation is based on a study commissioned by the Finnish Energy Industries entitled Mikrotuotannon liittäminen yleiseen sähkönjakeluverkkoon (Connecting very small-scale electricity generation to the public distribution network in Finland), and on the standard EN 50438 Requirements for the connection of microgenerators in parallel with public low-voltage distribution networks. 1. MARKINGS AND DEFINITIONS Micro-generation plant = An electricity generation plant connected to the low-voltage network at the consumption site, with the primary purpose of generating electricity to the consumption site. Feeding into the network is only occasional or insignificant. The size limit of single-phase production is 16 A (highest current fed by the plant). ROCOF relay = Rate Of Change Of Frequency relay, i.e. a relay measuring the change of the frequency rate Rear feed/reverse current = Rear feed means that a micro-generation plant can feed electricity into the network even when the feeding network is de-energised. Loss of Mains situation = A situation where the network or part of a network unexpectedly becomes de-energised. In such a situation, the micro-generation plant feeding to the site will not necessarily detect the shut-down of the network, but may continue to feed an isolated network of one or more sites. EMC = Electromagnetic compatibility 2. DEFINITION OF MICRO-GENERATION AND RESTRICTION ON SINGLE-PHASE PRODUCTION Micro-generation is electricity generation that is primarily meant for own use at the consumer’s installation, and feeding to the network is occasional or insignificant. In these generation installations, feeding to the network is not the primary reason for electricity generation. Therefore, micro-generation mainly refers to small-scale electricity generation installations acquired by individual consumers or small-scale ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 3(20)

Network recommendation YA9:09 Connection of micro-generation to the electricity distribution network

enterprises, connected to the electricity system of their own place of consumption. Currently, the most common types of generation installations are wind farms, solar installations and very small biofuel plants. 2.1. Definition of micro-generation This network recommendation focuses on generation installations, which are primarily meant to generate electricity for the installation’s own use and for which feeding to the network is only a secondary motive. The recommendation is based on a study commissioned by the Finnish Energy Industries entitled Mikrotuotannon liittäminen yleiseen sähkönjakeluverkkoon (Connecting very small-scale electricity generation to the public distribution network in Finland), and on the standard EN 50438 Requirements for the connection of micro-generators in parallel with public lowvoltage distribution networks. Both of these primarily deal with installations rated up to 3x16 A. Therefore, the maximum output of a micro-generation installation can be defined at approximately 11 kW. However, a network company may also use this recommendation to connect generation that is a grade higher. 2.2. Restriction of single-phase generation Single-phase generation that is too high will cause an imbalance in the network, jeopardising the safety and reliability of the network. Connection is permitted for a single-phase generation rated up to 16 A. Therefore, the maximum output of a singlephase micro-generation installation may be approximately 3.7 kVa. The nominal rated capacity of the installation is smaller and depends on the properties of the installation. The micro-generator must notify the system operator to which phase the single-phase generation will be connected, and the system operator must be able to have an impact on the phase if it so wishes. 2.3. Quantity of micro-generation in the place of use Generation may be connected to the place of electricity use in accordance with the output defined in the connection contract if the installation’s start-up or falling off the grid will not result in a change in voltage of over 4% and the quality of electricity in the connection point always remains within the limits of SFS-EN 50160. Moreover, the start-up current of the micro-generation installation must not exceed the peak value of current in accordance with the maximum output in the connection contract. It should be noted as background information that, according to Sener’s instruction (2001), connecting a small-scale power plant to the grid may normally be permitted if the short-circuit output Sk of the connection point satisfies the equation S k ≥ 25 ⋅ i ratio ⋅ S N . The limit is based on the fact that this design value can guarantee that connection of the small-scale power plant to the grid will not result in a voltage change of over 4%. This design principle is presented in the Tuuliverkko final report of the University of Vaasa and VTT. ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 4(20)

Network recommendation YA9:09 Connection of micro-generation to the electricity distribution network

Sener’s instruction has been given to all small-scale power plants, and it cannot necessarily be applied to the management of micro-generation. There is still such a small amount of experience in the impact of micro-generation on the grid that it is not possible to give an absolute ratio for its quantity and the size of the installation. The following is an example of what following the Sener instruction (2001) would mean in practical terms for the quantity of micro-generation. According to Sener’s instruction, an installation with a maximum output of S N =

Sk 25

may be connected to the grid if it is assumed to that the iratio is almost 1, i.e. the installation is not obtaining considerably higher switching current than its rated current. Based on the protection terms of the grid, the design value of the short-circuit output of low-voltage network connections is currently regarded to be at least 250 amperes ( I k = 250 A ). In some older connections, the short-circuit current is even smaller than this.

Short-circuit current I k = 250 A corresponds with short-circuit output S k = 3 ⋅ I k ⋅ U v = 3 ⋅ 250 A ⋅ 230V = 172,5kVA as three-phase output of the low-voltage network. This would mean that only a generation installation of a maximum of 172,5kVA SN = = 6,9kVA could be connected to an installation with a short-circuit 25 current of 250 A. 3. DISCONNECTION OF THE INSTALLATION AND OCCUPATIONAL SAFETY IN THE NETWORK This chapter deals with the occupational safety requirements for the operations of a micro-generation installation and safe working methods. 3.1. Disconnection of the installation and safe working in the electricity network According to the electrical safety standards, it must be possible to disconnect a generation plant from the network, the disconnecting device must have a visible air clearance, and it must be possible to lock the operating mechanism of the disconnecting device (SFS6002). Moreover, the distribution system operator must have either unrestricted access to the disconnecting device or a possibility for remote disconnection (SFS6000).

In network maintenance and repair situations, it is important that the micro-generation installation does not maintain the network voltage. The micro-generation installation’s own protection must ensure that the installation does not feed into a zero-voltage network. However, the standards require an additional disconnecting device in order to ensure installation safety during work on the network. A separate disconnecting device installed in connection with the micro-generation plant can be used as a disconnecting device if it has a visible air clearance or a reliable ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 5(20)

Network recommendation Connection of micro-generation to the electricity distribution network

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mechanical position indicator, or the main fuses of the power room of the site can be detached. In repair and maintenance of the network, it must be ensured that the disconnectors are used appropriately. The disconnecting device may also be a switch located before the connection point in the system operator’s network. For example, a pole mounting fuse-switch in an overhead line network or a HRC fuse switch in a cable branching board in the cable network. The micro-generator can be invoiced for the installation of this kind of a switching device only if this kind of a switch would not have otherwise been installed in the network and if the micro-generator had not installed an appropriate disconnector in connection with its generation installation. An alternative for using disconnectors is to carry out the work as appropriate voltage work or otherwise in an equally safe way. 3.2. Taking account of the rear feed risk As micro-generation becomes more common, generation installations that have been connected to the grid without the system operator’s permission will pose a possible hazard. The system operator is not aware of the location or protection of these installations.

Due to the rear feed risk, it is important to establish zero voltage and to earth the place of installation on the side of any micro-generation installation. In a low-voltage network, it is also advisable to carry out earthing on both sides of the work site whenever there is a possibility that small-scale generation has been connected to the network, and earthing on the side of the site is possible. 3.3. Marking of micro-generation sites Micro-generation outputs must be marked appropriately on the side of both the installation and the network. In practice, all sites that can be made live by the micro-generation installation must be marked. These sites include transformer outputs and any branching boards. The customer’s own power room must also be appropriately marked with a warning that micro-generation has been connected to it. The texts of the warning signs must be informative and in an appropriated place, and they must be in Finnish. It is also advisable that the system operator marks each micro-generation installation in its own systems so that an electrician may be provided with advance information regarding which connection sites have micro-generation. The network data systems must be developed so that these markings can be carried out.

The warning signs must be positioned so that any electrician or layman on site will definitely see them. Furthermore, it is important to provide installation personnel with instructions on the meaning of the warning signs, how the risk posed by the microgeneration installation must be taken into account in practical work and how to ensure zero voltage of the site. Warning is given on the existence of small-scale and micro-generation installations in the distribution network by adding the marking in connection with the transformer substation ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 6(20)

Network recommendation Connection of micro-generation to the electricity distribution network

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or branching board output. If necessary, warning of generation may be given with a written sign with a yellow background. The text of the warning sign may be as follows: ‘Electricity generation installation. Beware of reverse current.’

4. QUALITY OF ELECTRICITY FED BY THE INSTALLATION Micro-generation operating in parallel with the network must not cause any disturbance in the network or in other electrical installations. If a micro-generation installation connected to the network causes disturbances elsewhere in the electricity network, the system operator must take measures and, if necessary, have the installation removed from the network. 4.1. EMC requirements The following is a list of standards on EMC requirements, which can be applied to micro-generation installations. • • • •

Interference immunity: EN 61000-6-1 Electromagnetic compatibility (EMC) Generic standards Immunity for residential, commercial and light-industrial environments Electromagnetic emission: EN 61000-6-3 Electromagnetic compatibility (EMC) Generic standards Emission standard for residential, commercial and lightindustrial environments (also Appendix A11) Harmonic current emissions: EN 61000-3-2 Limits for harmonic current emissions (equipment input current up to and including 16A per phase) Voltage fluctuations and flicker: EN 61000-3-3 Electromagnetic compatibility (EMC). Limits. Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current up to and including 16 A per phase and not subject to conditional connection

Moreover, requirements for micro-generation have been gathered in a technical report currently under preparation: EN 61000-3-15 Electromagnetic compatibility (EMC) Limits – Assessment of low frequency electromagnetic immunity and emission requirements for dispersed generation systems in LV network. 4.2. Quality of electricity When a micro-generation installation is added to a metering point, the quality of voltage in the connection point must still comply with the standard SFS-EN 50160 Voltage characteristics of electricity supplied by public distribution systems.

The total harmonic distortion may be a maximum of 8% in the connection point. The amount of total distortion must not be exceeded even if micro-generation is connected to the connection point. Furthermore, the standard provides limits to individual harmonic current emissions, flicker and fluctuations of voltage levels.

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Network recommendation Connection of micro-generation to the electricity distribution network

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5. NETWORK CONNECTION OF THE INSTALLATION AND TRIPPING IN NETWORK FAULT SITUATIONS The micro-generation equipment must be fitted up with protection devices that switch off the equipment from the public network if the network feed is disconnected or if the voltage or frequency in the poles of the generator equipment deviates from the voltage and frequency values set for the permitted operation of the micro-generation installation. The micro-generation equipment must never be connected to the network when the network voltage or frequency is not within the given limits.

The protection of the installation must ensure that the micro-generation installation stops feeding to the network when any of the parameters listed in section 5.2 exceed or fall short of the set value. The installation must be disconnected in all equipment faults, and it must never start feeding electricity to a network if it does not meet the requirements of the set values presented in section 5.2. The equipment suppliers must always guarantee that the protection of the equipment meets the disconnection requirements laid down in legislation and standards. The protection equipment may be connected to the equipment of the micro-generation installation or it may consist of separate sets of equipment. The standard ‘EN 50438 Requirements for the connection of micro-generators in parallel with public low-voltage distribution networks’ sets out the requirements for a micro-generator to be connected to the network. A recommendation for the terms and conditions for connection to and disconnection from the network is presented in the following. With regard to standard EN 50438, it must be noted that the parameters defined in the standard vary to a great extent in different countries. Therefore, an installation meeting the general section of standard EN 50438 does not necessarily meet the requirements set especially for Finland in the standard. 5.1. Protection properties of the generation installation The protection equipment to be connected to the micro-generation installation must disconnect the installation from the network with appropriate mechanical contactors or electronic switches. If an electronic switch is not working, the installation must stop generating electricity or disconnect itself from the network in another way. An electronic switching device must be specified according to the overvoltage classification specified by the manufacturer, and the out-switched bleed current must not exceed 0.1 mA regardless of the terminal voltage. 5.2. The set values and operating times of parameters The micro-generation installation must disconnect from the network if the network voltage or frequency do not remain within the given limits. These limits are given in standard EN 50438 and presented in Table 5.1.

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Network recommendation Connection of micro-generation to the electricity distribution network

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Table 5.1. The set values for the protection of the connection point, two-stage protection Un is the rated voltage. Parameter Operating time Set value Overvoltage -level 1

1.5 s

Un + 10%

Overvoltage -level 2

0.15 s

Un + 15%

Undervoltage-level 1

5s

Un - 15%

Undervoltage-level 2

0.15 s

Un - 50%

Overfrequency

0.2 s

51 Hz

Underfrequency

0.5 s

48 Hz

Loss of Mains* 0.15 s *Loss of Mains protection, i.e. protection to prevent island use must use detection technologies suitable for the distribution network.

If it is not possible to implement two sets of over- or undervoltage limits with the protection equipment, one set of limits must be combined from the limits of the table. Thus, the requirements are stricter if there is only one set of voltage limits in use. These limits are presented in Table 5.2.

Table 5.2. The set values for the protection of the connection point, single-stage protection Un is the rated voltage. Parameter Operating time Set value Overvoltage

0.15 s

Un + 10%

Undervoltage

1.5 s

Un - 15%

Overfrequency

0.2 s

51 Hz

Underfrequency

0.5 s

48 Hz

Loss of Mains* 0.15 s *Loss of Mains protection, i.e. protection to prevent island use must use detection technologies suitable for the distribution network.

5.3. Synchronisation with the network The installation’s synchronisation with the network must be fully automated. The protection of the connection point must guarantee that the power feed to the network will not start until the voltage and frequency have stayed within the limits permitted by the protection settings at least for a certain minimum period, which is 3 minutes for generators and 20 seconds for systems connected with a frequency converter. ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 9(20)

Network recommendation Connection of micro-generation to the electricity distribution network

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It is recommended to perform re-synchronisation with the network after the fault in a staggered way, especially if there are several micro-generation installations behind the connection point. Staggering is possible to be carried out, for example, so that after the network voltage and frequency have returned to the permitted limits the frequency converter is synchronised with the network with a random delay of 0–15 seconds. This means that the synchronisation time after the return of the voltage would be 20–35 seconds. 5.4. Loss of Mains protection A micro-generation installation must always disconnect from the network in a Loss of Mains (LoM) situation, i.e. when the network voltage is lost. A micro-generation installation must never remain alone to feed an isolated network.

Some of the network connection devices feed power to the network in pulses and not as alternating current. In such a case, the network connection devices will not be able to remain in isolated network operation, but need constant network voltage for synchronisation. These device solutions do not need separate LoM protection. However, the devices must also be type tested in a LoM situation. On the other hand, it is possible with some network connection devices that if the loads of the isolated network are, by coincidence, very close to the combined production of one or several micro-generation installations, the installation will not be able to detect a LoM situation with voltage and frequency relays alone, but remains to feed the isolated network. In such a case, the devices must be equipped with LoM protection. The LoM protection must disconnect the installation sufficiently quickly. The operating time must be as quick as in a situation Un – 50%. The operating time of LoM protection is 0.15 s. Some of the so-called active LoM protection methods cannot necessarily be trusted to operate sufficiently quickly. Furthermore, some protection methods have been noticed to cause unnecessary tripping of installations from the network when large reactive loads are connected to the network. For these reasons, some of the active LoM protection methods are banned, for example, in Denmark. Therefore, a ROCOF relay with an operating time of 0.15 s or another protection method that is as fast and reliable as the ROCOF relay are recommended as LoM protection. The protection method must not cause extra problems in the network, such as unnecessary disconnection of generation. 5.5. High-speed autoreclosers In certain cases, micro-generation may have an impact on the high-speed autorecloser automation in the network. The operating time of the installation’s disconnection is 0.15 s. If the high-speed autorecloser time is, for example, 0.5 seconds, it is possible that the zero voltage time preceding the high-speed autorecloser will remain at 0.35 seconds (0.5 s – 0.15 s). If the micro-generation is found to cause problems in highENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 10(20)

Network recommendation Connection of micro-generation to the electricity distribution network

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speed autoreclosers, the high-speed autoreclosers in the network can be prolonged by 0.15 seconds in network sections with micro-generation and where high-speed autoreclosers are in use. 5.6 Use of reserve power If a consumer wants to use a micro-generator as reserve power in parallel with the network, the possibility of a dual connection mode must be installed, with one connection to work in parallel with the network and the other in an isolated network that is completely separated from the network. This requires a separate switch and additional devices. It is of utmost importance that the installation may under no circumstances concurrently feed both the network and the isolated network. 6. SHORT-CIRCUIT CURRENTS FED INTO THE NETWORK BY THE INSTALLATION A micro-generation plant may feed short-circuit currents into the network, thus increasing the overall short-circuit currents close to the fault location. High short-circuit currents in the vicinity of a distributed generation plant may result in exceeding the thermal limits in the network components. Especially cable connections, transformers and switching devices are problematic in a situation with increased fault currents. If the above-mentioned problems appear due to micro-generation, the problem may be managed, for example, by replacing components with better ones or by diminishing short-circuit currents by dividing the network into smaller sections. Resetting of transformer values may also reduce short-circuit currents. In some cases, fault current limiters may also be used.

The fault current fed by the micro-generation installation depends on the installation’s properties. The fault current of an installation connected to the network with a frequency converter is limited by the properties of the frequency converter. The fault current fed by micro-generation installations is usually only slightly higher than its rated current. The amount of maximum fault current of the equipment should be entered in the type testing documents of the installation. This value can be used when calculating the installation’s network impacts. The customer must notify the network company of the maximum amount of fault current fed by the installation. Two possible cases where the fault currents of micro-generation may result in faulty functioning of network protection are presented in the following. The cases are fault trip and fault in protection. Neither case is very likely when the amounts of micro-generation are small. However, the situation may change if the amounts of micro-generation increase considerably. The situation will become increasingly likely if micro-generation is produced by an asynchronous machine. The feeding ability of fault current in production connected with a frequency converter is restricted by the internal properties of the frequency converter, but an asynchronous machine may feed large amounts of short-circuit current. ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 11(20)

Network recommendation Connection of micro-generation to the electricity distribution network

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6.1. Fault trip A problematic situation in terms of network protection may arise in a case presented in Figure 6.1 where a micro-generation installation causes an unnecessary disconnection of a certain network section from the feed.

Figure 6.1. Fault trip. The fault current fed by a micro-generation installation is marked with red.

When a short-circuit fault takes place in a feed of a transformer substation that has another feed connected to distributed generation, the operation of over-current protection may be disturbed. In a fault such as in Figure 6.1, the feeding transformer feeds the fault current to the place of fault. The micro-generation installation also takes part in the feed of fault current. In such a case, fault current also flows through the over-current protection (fuse or relay) on the left-hand side. If the amount of fault current exceeds the capacity of over-current protection and the protection does not recognise the direction of fault current, it will operate and cut off the feed from the section of network on the side of the micro-generation installation. 6.2. Fault in protection Another problematic situation in terms of network protection may arise in a case presented in Figure 6.2 where the fault currents fed by a micro-generation installation disturb the operation of network protection.

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Network recommendation Connection of micro-generation to the electricity distribution network

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Figure 6.2. Fault in protection. The fault current fed by a micro-generation installation is marked with red.

When a fault occurs in a location where there are one or more micro-generation installations between the fault location and feed, the protection may become faulty. A situation where short-circuit current is fed to the place of fault is presented in Figure 6.2. However, the micro-generation installation in the figure also feeds fault current, in which case the fed fault current will diminish. If there is a sufficient amount of microgeneration, the fed short-circuit current may diminish to such a level that the overcurrent protection of the transformer output will no longer react. 7. SITES WITH NO BUYERS FOR ELECTRICITY It may be difficult to find a buyer for the electricity produced by micro-generation installations. Legislation does not impose a purchase obligation on any market party, ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 13(20)

Network recommendation Connection of micro-generation to the electricity distribution network

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and the system operator’s role as the buyer of electricity is in conflict with the operating principles of the electricity market and the roles and areas of responsibility laid down for various players. According to the current terms of contract, feed to the network should be prevented if no buyer is found for the electricity. However, the system operator can be flexible in this matter until the producer finds a market partner or the matter is solved, for example, with an amendment to legislation. When the producer finds a market partner, normal obligations concerning the producer enter into force. If a producer wants to connect a generation installation to the network even if there is no buyer for the electricity, the producer must conclude a separate contract with the network company. This kind of a contract model is dealt with in section 9.2. 8. METERING OF MICRO-GENERATION Metering practices and legislation on metering are different in various sites depending on the size of the facility and whether the electricity transmitted to the network is sold on the market. The different situations are dealt with in this section. The costs arising from the metering are dealt with in section 10. Pricing principles. 8.1. Sites with no electricity sold on the market A site, the electricity of which is fed into the network but not sold on the market, can be compared to a pure electricity consumption place. Legislation does not recognise a situation where the electricity fed to the network is not sold on the market. In these sites, it is possible to use the traditional rotating meter that measures only consumption, i.e. it measures only in one direction. It is not permitted to use a net meter.

However, it is also recommended to install hourly metering equipment in these sites. If these sites want to sell electricity fed into the network on the market at a later date, the equipment will have to be changed in any case. It is not recommended to charge the customer for this kind of a change of meter because, in practice, electricity transmitted to the network is metered only to meet the needs of the system operator. 8.2. Sites with a maximum of 3x63 A with electricity sold on the market The electricity generation must be metered with a remotely read electricity meter that is read by the hour. All existing generation sites from where electricity is also transmitted to the public distribution network must be equipped with hourly metering by the end of 2010 at the latest. New generation sites must be equipped with hourly metering with immediate effect.

When a small-scale generation site has both electricity generation and consumption, they can be metered with a single meter. An electricity generation plant connected to a metering site that is equipped with main fuses of a maximum of 3 x 63 A does not require a separate metering device, as it is enough that electricity acquired from the network and electricity fed into the network are metered separately at the site. ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 14(20)

Network recommendation Connection of micro-generation to the electricity distribution network

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Network input and output must not be netted, but the metering device must have separate registers for these. 8.3. Sites of over 3x63 A with electricity sold on the market If a generation plant is located at a metering point exceeding 3 x 63 A, generation and consumption can no longer be metered with just one meter. In addition to network input and output, consumption of own generation must be metered at a metering point with network input and output. Consumption of own generation is obtained by deducting from the generated electricity the production plant’s electricity for own use and the electricity fed into the network. Electricity for own use is electricity consumed by the production plant system itself.

Figure 8.1. Metering of generation.

The system operator is responsible for the metering of network input and output. The meter is owned by the system operator who also conducts its reading. The electricity generator is responsible for metering the consumption of its own generation. 8.4. On meter properties Various remotely read meters deal with phase-specific power transmission in different ways. There are remotely read meters that turn the readings processed by the meter into intrinsic values before sending them on. This kind of a meter is useless at a generation site because then the energy fed into the network is seen in the meter as energy obtained from the network. A net meter, which meters both ways and sums up the metering data, must not be used under any circumstances when the site has both consumption and generation. It is also not recommended to use a meter that sums up the generation and consumption metering results in different phases. 8.5. Registration and transmission of metering data When one metering point has both consumption and generation, they must be metered separately. The meter must record network input and output in different registers. Data management is carried out so that two metering point IDs are created for the site in the ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 15(20)

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network company’s system, one for the consumption site and the other for the generation site. 9. CONTRACTS ON GENERATION When generation is connected to a place of consumption, a separate contract is drawn up for the generation. For consumption, the Terms of Network Service (VPE) are complied with.

All connection points where feeding of electricity into the distribution network has not been prevented must comply with the terms of connection and network services concerning places of electricity generation. According to the Terms of Network Connection for Production (Sähköntuotannon liittymisehdot, TLE) and the Terms of Network Service for Production (TVPE), the customer must conclude generationrelated contracts on connection and electricity network with the distribution network operator when the customer feeds electricity into the public distribution network. This applies to sites feeding electricity that is sold on the market. 9.1. Technical information on the micro-generation equipment to be notified to the network company The producer of micro-generation must deliver information on the technical properties of the generation equipment to the system operator.

The producer must provide the following information before the connection is carried out. The system operator will grant the connection permit on the basis of this information, inter alia. • Information recorded in the nameplates of the production equipment, network connection device and any auxiliary equipment, and the maximum fault current fed by the equipment • Testing record showing that the production installation meets the protection requirements presented in subsection 5.2. • Generation installation’s method of connection to the network (automatic/manual) and date of connection • Information about the installation’s disconnection solution and disconnector data • Testing records showing that the equipment meets the EMC requirements presented in section 4 When the device is connected to the network, the producer must provide the system operator with an appropriate commissioning inspection record. If the installation has a single phase, it must be indicated to which phase it is connected. The generation plant may not be used until the commissioning inspection record has been delivered to the system operator and the system operator has given permission for the use of the plant. ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 16(20)

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9.2. Sites not selling to the market When so-called surplus electricity, i.e. electricity without a buyer, is transmitted to the network, normal contracts concerning the place of electricity use is drawn up on the use of the electricity at the site, and a separate contract is drawn up with respect to generation. In this subsection, it is recorded how to apply existing contractual terms in these contracts and what kinds of extra notes can be made in the contracts.

Section 4 of the Terms of Network Service for Production (TVPE) may be applied to the surplus electricity contract, with definitions of technical terms and for the generation installation and its use. The Terms of Network Service (VPE) may also be used where applicable. If applied, section 4 of TVPE should be attached to the contract. An alternative is to apply TVPE only, where applicable. A separate contract on surplus electricity only applies to a generation site with no buyer for the electricity transmitted to the network. The contract is terminated if the electricity transmitted to the network is sold on the market. In such a case, a contract on the network service of generation is concluded with the system operator, applying the contractual terms of generation. For example, the following matters may be recorded in the contract. •

No compensation will be paid for electricity transmitted into the network, and no network service fee for production will be charged with respect to electricity transmitted into the network. Normal network service fees will be charged for network input, i.e. consumption.

•

The generation installation may not be connected until the producer has delivered to the system operator the technical data of the generation installation and the appropriate commissioning inspection record, and the system operator has given permission for the connection of equipment. The system operator must be informed of the connection or removal of equipment. If the equipment or connections are changed, it can be regarded as a new installation, and information on a commissioning inspection carried out after the change must be delivered before commissioning.

•

The arrangement of metering may be mentioned in the contract, for example, as follows: ‘The system operator shall be responsible for arranging the metering and the metering of electricity at the site. The site is metered with a unidirectional meter that meters consumption only. Electricity fed into the network is not metered separately. The system operator is entitled to replace the meter with a bi-directional, remotely read metering device at a later date (without a charge). ”

•

The system operator is entitled to terminate the contract at three months notice if it is unreasonable to keep the contract in force due to an amendment to legislation or an essential change in circumstances (TVPE 14.6). ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 17(20)

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•

Furthermore, the system operator is entitled to terminate the contract with a period of notice it deems suitable if the standardisation or generally accepted guidelines on the matter are changed.

•

The producer is obliged to notify the system operator if he concludes a contract on selling the energy fed into the network.

•

The producer is obliged to notify the system operator of any changes to be made to the generation installation or its connection and of any other changes that may have an impact on the contract.

•

It is advisable to record in the contract as information for the microgenerator that if the micro-generation installation keeps on feeding an isolated network due to faulty operations and equipment connected to the network becomes faulty as a result of isolated network operation, the producer who has fed electricity into the isolated network is liable to pay compensation to the system operator for any damages to be compensated for by the system operator. Correspondingly, the producer himself is liable to the producer of isolated network use for the damages caused.

•

Section 4 of the Terms of Network Service for Production (Sähköntuotannon verkkopalveluehdot, TVPE) deals with the terms and conditions related to the use of electrical equipment and electricity generation equipment. This section may be applied in the contract. The issues included in the section are listed in the following: o Compliance of regulations concerning electrical equipment o Electrical safety of electrical equipment o Commissioning of electricity generation equipment o Use, guidance and protection of electrical equipment o Quality requirements for electricity o Fault, disturbance and damage situations of electrical equipment

10. PRICING PRINCIPLES This chapter specifies the pricing of connection fees and network service charges for micro-generation sites. 10.1. Connection fee The system operator must connect the metering sites and electricity generation plants that meet the technical requirements in its area at request and for a reasonable charge. According to Section 14 b of the Electricity Market Act, the connection fees for generation by a maximum of 2 MVA plants must not include costs resulting from the strengthening of the electricity network. Therefore, it is permitted to charge only for the costs arising from the section of network serving the site itself. If the connection of the ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 18(20)

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generation installation causes protection changes in the network, the customer is also responsible for these costs. 10.2. Amount of connection fee when the site’s consumption is greater than its generation If the site’s consumption (network input) is greater than the generation of the site (network output), the normal connection fees for the place of use shall be charged. This situation usually applies to small-scale generation. 10.3. Amount of connection fee when the site’s consumption is smaller than its generation If the site’s consumption (network input) is smaller than its generation (network output), the size of the connection required for consumption only shall be estimated, and a connection fee for a place of consumption of a similar size shall be charged. For the exceeding part, it is possible to charge an imputed proportion corresponding to the principles of the connection fee for generation.

The above-mentioned imputed proportion may be determined, for example, as follows: Its amount corresponds to the construction costs of a network serving a customer of a connection with a size corresponding to the customer’s generation, deducted by the construction costs of a connection corresponding to the customer’s consumption with respect to the network serving the customer. 10.4. Network service fee According to the Electricity Market Decree (Government decree on the electricity market), a maximum network service fee for production at 0.07 cents/kWh (VAT 0%) may be charged for generation connected to a low- and medium-voltage network. Moreover, metering services and other additional services may also be subject to a fee. Normal fees will be charged for consumption (network input). Consumption of own generation is usually subject to a fee only in installations of more than 1 MVA. This is due to the definition principles for grid fees.

Sites whose generation is not sold on the market cannot be charged for a network service fee for production or a fee for the metering of generation. 10.5. Metering costs When a meter has to be replaced with a new one at a site due to micro-generation, the system operator may charge the site for the costs arisen from the replacement, i.e. a one-off metering fee. The meter itself is paid for by the system operator because it is the system operator’s property. With regard to sites with an existing hourly meter, the system operator may charge a so-called programming fee, a fee for the introduction for the bi-directional metering facility.

The system operator may also invoice the site for a so-called constant metering fee, which may be different from the metering fee of the consumption site alone. The metering fee or the basic fee for the network service charged from sites with both consumption and generation sold to the market may justifiably be slightly higher than ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 19(20)

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those of the consumption site alone because in such a case, e.g. the balancing data of the sites will be doubled. It is not justifiable to charge metering fees for generation from sites where the electricity transmitted to the network is not sold on the market.

ENERGIATEOLLISUUS ry PL 100, 00101 Helsinki Puhelin: (09) 530 520, fax: (09) 5305 2900 Sivu 20(20)