Aforo Anual Ponderado
RESULTADO INTEGRAL DE FINANCIAMIENTO:
The purpose of the NS protection is to disconnect the power generation system from the net in the event of inadmissible voltage and frequency values (also see DIN VDE 0100-551 (VDE 0100-551), 8.2.) This is intended to prevent an unintentional feed-in of the power generation system into a power-supply unit separated from the remaining distribution network as well as the feed-in of faults within this network.
The specifications given in 6.5.2 do not refer to the protective functions short-circuit protection, overload protection, protection against electric shock and all-phase separator of the circuit to the power generation system (e.g. by means of line circuit breakers, earth leakage circuit breakers) which shall be executed in accordance with the applicable VDE regulations and for which the connection owners are themselves respon- sible (to ensure self-protection). In this respect, the protection function described in this VDE application guide may have to be extended by the connection owner as appropriate to the power generation system. However, the self-protection shall not undermine the requirements described in this VDE application guide. The system operator shall himself take precautions to prevent damages to his systems and installations as might be caused by switching actions, voltage fluctuations and automatic reclosings in the network connected upstream or other processes in the network of the network operator.
The following functions of the decoupling protection shall be implemented: – voltage drop protection U<;
– rise-in-voltage protection U>;
– rise-in-voltage protection U>>;
– frequency decrease protection f<;
– frequency increase protection f>;
– islanding detection.
Voltage protection devices should utilise the half-wave r.m.s. value. For this, using the 50 Hz fundamental component is sufficient.
Only the rise-in-voltage protection U> shall be designed as 10-minute running mean value protection which prevents the upper voltage limit specified in DIN EN 50160 from being exceeded (monitoring of the power
quality). For this, formation of a new 10-minute mean value at least every 3 seconds is sufficient, which is then to be compared with the setting value for U> given in Table 2.
Voltage protection devices shall be constructed so, that they monitor the supplying (feeding) line conductors. For power generation systems of up to 30 kVA, the voltage(s) (per line conductor supplied) shall be measured between the line conductors and the neutral conductor.
Voltage protection devices for power generation systems of more than 30 kVA shall be constructed as three- phase equipment. To this end, the three voltages between the line conductors and the neutral conductor shall be measured; the three line-to-line conductor voltages shall either be determined arithmetically from the three line-to-neutral voltages or else also be measured separately. Thus, recording of 2 × 3 voltage values is required for this.
The voltage values shall be composed by disjunction (logical OR). Disjunction means in this case that: – for rise-in-voltage protection relays, exceeding the threshold value leads to an excitation for at least one
measuring voltage;
– for voltage-drop protection relays, a drop below the threshold value leads to an excitation for at least one measuring voltage.
Frequency protection devices may be designed as single-phase equipment.
The setting values of the protective functions and the last five dated failure reports (a relative time stamp is sufficient, i.e. a real time clock is not required) shall be readable at the NS protection. Interruptions of supply with durations of 3 s or longer shall not lead to loss of any of the failure reports. Read-out shall be possible at the central NS protection irrespective of the operational state of the power generation system and without any additional aids (such as a display). For integrated NS protection read-out may be carried out using a data interface. Power generation systems with integrated NS protection and a maximum apparent power
SAmax≤ 4,6 kVA are exempt from the requirements of this paragraph until 2012-12-31.
6.5.2 Protective functions
Except for the rise-in-voltage protection U>, all protective functions shall be firmly set in the NS protection (i.e. so as to be unalterable).
The protective functions of the NS protection shall be designed so that the disconnection time (i.e. the sum of the proper times of NS protection and interface switch plus a delay for the protection relay, which may or may not be adjustable) does not exceed 200 ms. The following protective functions shall be set in the NS protection.
Table 2 — Setting values for the NS protection
Protective function Protection relay setting values*
Voltage drop protection U< 0,8 Un < 100 ms
Rise-in-voltage protection U> 1,1 Un** < 100 ms
Rise-in-voltage protection U>> 1,15 Un < 100 ms
Frequency decrease protection f< 47,5 Hz < 100 ms
Frequency increase protection f> 51,5 Hz < 100 ms
* The duration set point “< 100 ms” for the protection relay setting value is based on the assumption that the maximum proper time for both NS protection and interface switch is also 100 ms. This leads to a maximum total disconnection time of 200 ms. If the pro- per time of a component is less than 100 ms (e.g. 50 ms), then this allows for a longer period during which to perform the measurements and evaluation of the protective function (e.g. up to 150 ms). This could then lead to a protection relay setting value higher than “< 100 ms”, i.e. “< 150 ms”. However, in that case, only the 100 ms shall be visualised as setting value at the NS protection. Still, the disconnection time of 200 ms shall not be exceeded under any circumstance.
** It shall be ensured, that the voltage at the network connection point cannot fall below 1,1 Un. If compliance with this requirement is ensured by a central NS protection, then it is permissible to set the rise-in-voltage protection at the decentralised power genera- tion unit or system to a value of up to 1,15 Un. In that case, the system erector should consider any possible effects on the customer installation. Combination of central NS protection (U>: 1,1 Un) and integrated NS protection (U>: 1,1 to 1,15 Un) is advisable, if the voltage drop does in the house installation cannot be neglected. This is typically the case with longer connection lines.
If only an integrated NS protection is used for power generation systems of up to 30 kVA, then the value of the rise-in-voltage protection U> of 1,1 Un shall not be changed.
The admissible tolerance between setting value and trip value of the voltage shall be at maximum ± 1 % and the admissible tolerance for the frequency at maximum ± 0,1 %.
The conditions for connection/re-connection of the power generation system are described in 8.3. 6.5.3 Islanding detection
For power generation systems, islanding detection shall be carried out using one of the following methods: a) active method, e.g. by means of a frequency shift method (generally for PV systems);
b) passive method by means of the three-phase voltage monitoring (possible only for power generation systems without inverters or for single-phase power generation units with inverters).
Method a) shall be verified by means of a resonant circuit test, whereas method b) shall be verified at an AC voltage source (see Annex D).
NOTE In special cases it may be necessary to use additional protective functions (e.g. vector surge or load step relays) in order to ensure decoupling or safe network operation. This is the case, e.g., if the output of power generation systems with rotating machines amounts to more than 20 % of the output of PV systems using the frequency shift method in the same local network. If so, then more powerful power generation systems should be equipped with rotating machines with vector surge relays.
The islanding detection is implemented in the central NS protection or in the integrated NS protection of the power generation unit. If an islanding detection system acting on the integrated interface switch is integrated in all power generation units of a power generation system, then it is permitted to omit the islanding detection in the central NS protection regardless of the system power.
Detection of an isolated network and disconnection of the power generation system by means of the interface switch shall be completed within 5 seconds.
7 Metering for billing purposes
Installation and operation of the measuring device Z1 shall comply with VDE-AR-N 4400:2011-08 (formerly BDEW guideline “Metering Code” [8]), the VDN guideline „Technische Anschlussbedingungen für den Anschluss an das Niederspannungsnetz“ (Technical connection conditions for connection to the low-voltage network; TAB 2007 [3]) as well as the connection conditions of the network operator. Load-profile meters shall be used for system powers of more than 100 kW.
Installation and operation of the measuring devices shall be agreed in due time between the system operator and the network or metering point operator, respectively. According to the German Calibration Act (Gesetz über das Mess- und Eichwesen or Eichgesetz for short), only certified and calibrated meters and transformers shall be used in the course of business.
A two-direction meter shall preferably be used as meter Z1 (see C.4.3) for extraction from the network operator’s network and for feed-in into the network operator’s network; alternatively, it is possible to use, for system powers of up to 100 kW, one backstop measuring device each for extraction and feed-in on separate meter sections. The execution shall be co-ordinated with the network operator. The measuring devices (Z1) used for extraction and feed-in in conjunction with power generation systems shall be constructed so that a measurement procedure balancing over all phases is ensured separately for the two current flow directions. Electronic three-phase meters shall be parameterised in accordance with the Ferraris principle with regard to the backstops and recording of two directions. Therefore, the meter point-related balance shall first be calculated for the three line conductors after which it is required to apply the “backstop” function to this balance or to carry out the allocation to the meter “extraction” or “feed-in”, respectively.
In order to ensure correct metering of the generation quantities supplied to the customer system in accord- ance with EEG 2009 [6], § 33 (2) or of the CHP net current generation in accordance with KWK-G 2009 [7], § 4 (3a), the only meters to be installed as meter Z2 (see C.4) shall be backstop meters. Separate meters Z2 shall be installed for each type of system (e.g. PV or CHP system). A separator shall be installed between the meter Z2 and the customer system (see Figure C.6 and Figure C.7 of C.4.3). It is not permitted to allocate the three line conductors of a power generation unit feeding into the three-phase system to different measuring devices (e.g. for full feed-in and excess feed-in). For photovoltaic systems with a maximum active power
PAmax of up to 30 kW and for CHP systems the system operator is free to chose whether to install the
measuring device Z2 at a central meter panel in accordance with TAB [3] or next to or inside the power generation unit (see 5.5).
In addition, the metrological framework conditions (e.g. temperature, humidity, operating position, mechanical influences) shall be adhered to.
NOTE This regulation replaces the specifications given in „Ergänzung zu den TAB 2007“ (Supplement to TAB 2007) [9].
The minimum requirements for the accuracy classes of the measuring devices are prescribed by the respective network operator. As a rule, the following accuracy classes shall be provided:
– energy meters: Class 2 (active energy);
– load-profile meters: Class 1 (active energy) or Class 2 (reactive energy); – current transformers: 0,5S.
In the case of load-profile meters, the system operator shall maintain a communication connection that can be used for remote transmission of the metered values. Data recorded by the network operator are treated as confidential and will only be made available to authorised persons.
The line colours for meters directly connected to a meter panel in accordance with TAB 2007 [3] shall be chosen as specified in DIN 43870-3:
– lines “lower connection compartment → meter”: black – lines “meters → main line branch terminal in the upper connection compartment”: brown
The meter section shall be marked so, that the label “power generation system” is durable and easily readable.
8 Operation of the system
8.1 General
The operation of electrical installations includes all technical and organisational activities required to ensure the functional efficiency and safety of the systems. These activities include all operating measures as well as electrical and non-electrical operations as described in the applicable rules and regulations. Particular reference is made to DIN VDE 0105-100 (VDE 105-100).
The system operator is responsible for the operation of the power generation system. If required by the network operator, the system operator shall name an electrically skilled person able to carry out the required works on the system operator’s electrical installation.
For connection of the power generation systems, the conditions given in 8.3 shall be satisfied. During operation, the conditions of Clause 5, which the decisions regarding the connection of the power generation system were based on, shall only be changed with the consent of the network operator.
The system operator shall ensure that the equipment required for parallel operation with the low-voltage network is always in proper technical condition. To this end, it is required to have an electrically skilled person check the switches and protective devices for proper functioning at regular intervals. This requirement is deemed to be satisfied for normal operating and environmental conditions if the test intervals mentioned in BGV A3 or TRBS 1201 are adhered to. The repeat tests shall include at least the following:
– check of the environmental conditions (pollution, mechanical or isolation damages) and elimination of deficiencies, if required;
– tripping control of the interface switch.
The result shall be recorded in a test protocol which shall be submitted to the network operator upon request. Regular repeat tests of the NS protection, the interface switch and the functional chain NS protection— interface switch may be omitted if a routine test has been conducted in the context of conformity checks (see G.3) and if a test certificate issued by a certification body appropriately accredited by DAkkS, the Deutsche Akkreditierungsstelle (i.e. the national accreditation body of the Federal Republic of Germany) in accordance with DIN EN 45011 is available.
In justified cases, the network operator can require a check of the NS protection and the interface switch in order to demonstrate their proper functioning.
Power reduction or disconnection required due to network conditions
Upon request of the network operator, the system operator is obliged to switch off the power generation system or to disconnect it from the network if this is required for conducting works that are necessary for operational purposes in the network operator’s network. Scheduled disconnections shall be announced to the system operator in a timely and suitable manner.
In case of danger, breakdown or risk to network security, the network operator is entitled to immediately disconnect the power generation system from the network or to reduce its active power, respectively.
In the event of the agreed maximum connection power being exceeded the network operator is entitled to disconnect the power generation system from the network. To this end, the network operator may require of the system operator to install adequately designed technical equipment that will separate the power genera- tion system from the network operator’s network as soon as certain limit values (e.g. the maximum apparent connection power) are exceeded.
If the network operator detects serious defects in the power generation system concerning the safety of persons and systems, then they are entitled to disconnect the system parts concerned from the network until the defects are rectified.
Access
Upon co-ordination with the system operator, the network operator shall be granted access to all components of the power generation system (meter panel, central NS protection (if available), interface switch, facilities of the power generation/network security management (if available), and the power generation units).
Exchange of information
The network operator will inform the system operator about substantial modifications in his network which will have an impact on the current parallel operation. The system operator shall, in due time, co-ordinate with the network operator any scheduled modifications to his power generation system which will have an impact on the parallel operation or the decoupling protection, such as increase or decrease of the system power, replacement of protective devices or modifications to the compensation equipment.
Coupling of network connection points
Different network connection points on the network of the network operator(s) shall not be operated in galvanic connection through systems of one or more system operator(s).
Behaviour in the event of disturbances
The reconnection conditions given in 8.3 shall be satisfied.
The system operator shall immediately inform the network operator about any incidents detected as far as they are of importance to the network operator.
Due to the possibility of voltage recovery at any time after an interruption of supply, the network connection point is to be considered to be constantly energised. Reconnection is usually carried out by the network operator without prior consultation with the system operator.
Fault clearance may require unscheduled investigations and measurements which the network operator and the system operator shall carry out on their respective operating equipment. For fault clearance and remedy, the network operator and the system operator shall provide mutual support. All information required for fault clearance shall be exchanged between them.
8.2 Particular characteristics of the management of the network operator’s network