JP2018033219A - Automatic power return system in one-line power reception extra-high power generating station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic power return system in one-line power reception extra-high power generating station, capable of avoiding causing inconvenience in application because a one-line extra-high power generating station has a higher possibility of interruption of service in a power transmission line for power source than a two-line power generating station; however, even after a power transmission line has interruption of service due to a power transmission line accident, time and trouble can be saved if the accident is removed by reclosing.SOLUTION: System interconnection of an electric power company transmission line and a power reception extra-high power transmission line (66 kV) is performed with one line, and an interconnection breaker of the system interconnection has been changed from a regular power reception breaker to a breaker on the secondary high-voltage side of the power generating station.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an automatic power recovery system in a one-line power receiving extra high power plant in the case where a power generation facility of a solar power plant is linked to a special high piezoelectric line of an electric power company.

  Grid connection is the state from the time when the power generation equipment is parallel to the commercial power system (connecting the power generation equipment to the commercial power system) to the time of disconnection (detaching the power generation equipment from the commercial power system) Say that.

  In addition, the grid interconnection may or may not have a reverse power flow for supplying power to the electric utility's power grid.

  FIG. 4 is an explanatory diagram at the time of normal power generation when the power generation facility of the solar power plant is connected to the special high piezoelectric line of the power company, PCS1 to PCS7 are solar panels of the solar power plant, and A is the power company substation. (154 kV / 66 kV), B indicates a power reception extra high (66 kV) transmission line to the electric power company transmission line A.

  Normally, the power transmission line is a connection of two lines, but the example shown is a case of only one line (single line connection).

  As power transmission line facilities on the electric power company side, 89ER1, 89ER2, and 89ER3 are earthing switches, 2 is a switch, O2 is a power receiving circuit breaker on the 66kV transmission line side of the power plant, and PT is an instrument transformer.

  The facilities inside the solar power plant are connected to the power company's transmission line facilities via the main transformer C, 52S is a transformer secondary circuit breaker, PT is an instrument transformer, and 52Fl and 52F2 are A breaker for each generator block as a secondary breaker of the main transformer.

  89ST is a switch for the in-house transformer, and Tr is an in-house transformer.

  When an accident occurs in the 66 kV power transmission line, the circuit breaker at the power substation is opened.

  In general, a solar power plant is configured to open the connection point O2 and solve the connection.

When O2 is opened, the power plant is completely stopped, and the problems in that case are as follows.
(1) Power generation is stopped.
(2) The operation storage battery begins to discharge. (It becomes inoperable after 4 hours)
(3) For restoration, the operator will go to the site and operate.
(4) The 66 kV power transmission line is automatically reclosed after 10 seconds. (Recycle success rate is over 90%)

  If the 66kV transmission line is out of power in the current daytime when guerrilla thunderstorms are frequent, the guerrilla thunderstorm is transient and the transmission line can be re-transmitted (after 10 seconds) and receive power. In spite of the situation that can be paralleled, since the engineer is not resident at any time because of the power plant control method of the patrol system, it takes about 3 hours until the engineer arrives at the site and parallels the power plant.

  In the meantime, it is not possible to obtain income from solar power generation until the power plants are paralleled.

  In this way, if the power receiving breaker (O2) is selected as the circuit breaker with the 66 kV transmission line, the engineer will be able to operate the power station even if the power receiving breaker (O2) is opened and retransmitted due to the 66 kV transmission line stoppage. It takes about 3 hours to arrive, during which time the charger stops and the battery cannot be charged.

  In addition, even if the battery overdischarges and a technician arrives at the power plant and attempts to restore the power plant, the device cannot be operated due to battery overdischarge.

  The object of the present invention is to eliminate the inconvenience of the conventional example described above, and in the 1-line extra high power station, there is a higher possibility of the power transmission line power outage than the 2-line power receiving power station. It is an object of the present invention to provide an automatic power recovery system in a one-line power receiving extra high power plant that can avoid inconvenience in operation because it is possible to save trouble if the accident is recovered by reclosing the electric wire.

  In order to achieve the above object, the present invention according to claim 1 is to perform grid connection between a power company transmission line and a power receiving extra high transmission line (66 kV) from a power plant in one line. The gist is that the interconnected circuit breaker is changed from a normal power receiving circuit breaker to a high-voltage circuit breaker on the secondary side of the main transformer on the power plant side.

  According to the first aspect of the present invention, the connection breaker with the 66 kV transmission line of the power plant is changed from the normal power receiving breaker (O2) to the high-voltage side breaker (52Fl / 52F2) of the main transformer secondary. As a result, when the 66 kV transmission line is retransmitted (10 seconds after the accident), the in-house transformer is charged and the battery can be charged, so that the battery discharge can be minimized.

  Also, by changing the interconnection breaker with the 66kV transmission line of the power plant, the power receiving breaker and the main transformer secondary breaker trip when an in-house accident occurs, and the interconnection breaker ( 52F1 and 52F2) By shutting off two units at the same time, it became easier to determine whether it was an in-house accident or a power transmission line accident.

  As described above, the automatic power recovery system in the one-line power receiving special power plant according to the present invention can greatly reduce the equipment cost because of the one-line connection, and conversely, the two-line power generation because of the one-line power plant. The possibility of power outage in the power transmission line is higher than the power station, but after the transmission line is stopped due to a power transmission line accident, if the accident is recovered by reclosing the power transmission line, it is possible to save time and use it. It is possible to prevent inconvenience in operation.

  According to the present invention, if the accident is recovered by reclosing the transmission line after the transmission line is stopped due to a transmission line accident, the engineer automatically enters the circuit breaker (52Fl / 52F2) before arrival at the power plant. Immediately connected to the 66 kV system, normal power generation can be continued.

  Also, an automatic power recovery system can be completed at low cost simply by configuring and adding an automatic power recovery device sequence.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing an embodiment of an automatic power recovery system in a one-line power receiving special power plant according to the present invention. PCS1 to PCS7 are solar panels of a solar power plant, a power company substation (154 kV / 66 kV) ( 4 (not shown, refer to FIG. 4), the grid connection between the power company transmission line and the power receiving extra high transmission line (66 kV) from the power plant is performed in one line.

  89ER1, 89ER2, and 89ER3 are earthing switches, 2 is a switch, O2 is a power receiving circuit breaker on the 66 kV transmission line side of the power plant, and PT is an instrument transformer.

  The above is equipment on the power transmission line side, and is connected to the inside of the photovoltaic power plant through the main transformer C.

  In the solar power plant, 52S is a transformer secondary circuit breaker, PT is an instrument transformer, and 52Fl and 52F2 are circuit breakers for each generator block as a secondary transformer high voltage side circuit breaker.

  89ST is a switch for the in-house transformer, and Tr is an in-house transformer.

  In the present invention, the circuit breaker with the 66 kV transmission line of the power plant is changed from the normal power receiving circuit breaker O2 to the high voltage side circuit breakers 52F1 and 52F2 of the main transformer secondary.

  The present invention can be realized by adding an automatic power recovery device sequence.

  In this sequence, when the 66 kV transmission line accident occurs, the power station is completely stopped, and when the secondary transformer high-voltage circuit breakers 52F1 and 52F2 are automatically shut off and the 66kV transmission line is successfully retransmitted, the receiving breaker O2 and the main transformer The condition is that the secondary breaker 52S is not interrupted (not an in-house accident).

  Based on this condition, after the elapse of a certain time after power reception, the secondary secondary high-voltage circuit breakers 52Fl and 52F2 are automatically automatically turned on and automatically paralleled if the generated voltage and system interconnection are possible.

  The transformer secondary high voltage side circuit breakers 52Fl and 52F2 are not automatically turned on when the accident is interrupted or manually opened.

  By doing so, the power receiving breaker O2 and the main transformer secondary high-voltage side circuit breakers 52Fl and 52F2 are tripped at the time of the on-site accident, and the two of the interconnection circuit breakers 52Fl and 52F2 are simultaneously operated at the time of the transmission line accident. Cut off.

  As a result, it is easy to determine whether the accident is an in-house accident or a transmission line accident.

  Further, when the 66 kV transmission line B is retransmitted (10 seconds after the accident), the in-house transformer Tr is charged and the battery can be charged, and the discharge of the battery can be minimized.

  The automatic power recovery device is activated only when a power line accident occurs by starting up the two circuit breakers, the power receiving breaker O2 and the main transformer secondary circuit breaker 52S, when the power failure occurs. This ensures the start of the automatic power recovery device.

FIG. 2 shows a flow at the time of a 66 kV transmission line accident.
1) Power outage due to 66 kV line accident 2) SGET power station fully shut down 3) (52F1, 52F2) Automatic shut-off (O2 / 52S) No trip, in operation 4) Successful re-transmission of 66kV power line after 10 seconds 5) SGET power station ( 66kV · 6.6kV) Busbar charging Power supply in the station 6) After a certain period of time (52Fl → 5 minutes later · 52F2 → 10 minutes later) Automatic input 7) Automatic parallelization after confirming voltage and phase at each PCS PCS1 to 7 sequential parallel 8) Normal power generation state

The sequence check of the automatic power recovery apparatus in the present invention was as follows.
(1) Direct test i) With respect to test conditions (O2 open / 52S open), the test is omitted because 27R is in an operating state.
ii) Remote test Because the direct test is satisfactory (operation test, interlock test, etc.), the remote test is conducted only by the grid interconnection protection relay (for isolated operation detection) 95RH operation.
(2) Countermeasures when 52F1 or 52F2 is stopped i) For the test item (NO33 or NO42), when the breaker is cut off by DGR, the circuit breaker state is received by the keep relay, so the input command from the automatic power recovery device is not output .
ii) Accident aspect Cable accident between feeder panel and current collector panel → DGR operation → (52F1 or 52F2 cut off) → Transmission line accident → Power plant full stop → (52F1 or 52F2 cut off) → Receiving power after 10 seconds → Automatic power recovery device start → 10 Minutes later (52F1 or 52F2 is charged) → The accident circuit breaker remains open.

  FIG. 3 shows an automatic shut-off circuit (trip circuit) for 52F1 and 52F2. 51F1 is an overcurrent relay, 50F1 is a grid connection protection relay (single operation detection) (generator abnormal voltage protection) (transmission line short circuit protection) (transmission line ground fault protection), 67GF1 is a ground fault direction relay, and 27R is all Indicates a stop detection relay.

  The merit of the introduction of the automatic power recovery device is that, after the transmission line is stopped due to a 66kV transmission line accident during the daytime, if the accident is recovered by reclosing the transmission line, a circuit breaker (52Fl / 52F2) will arrive before the engineer arrives at the power plant. ) Is automatically connected to the 66 kV system immediately and normal power generation can be continued.

It is circuit explanatory drawing which shows one Embodiment of the automatic power recovery system in the 1 line power receiving extra high power station of this invention. It is a flowchart at the time of the power transmission line accident of the automatic power recovery system in the 1 line power receiving extra high power station of this invention. It is a trip circuit diagram of a circuit breaker. It is circuit explanatory drawing which shows the condition at the time of the normal power generation in a power plant.

PCS1 to PCS7 ... Solar panel A ... Power company substation (154kV / 66kV)
B ... Received extra high (66kV) transmission line C ... Main transformers 89ER1, 89ER2, 89ER3 ... Earth switch 2 ... Switch O2 ... Receiver circuit breaker PT on the 66kV transmission line side of the power plant ... Instrument transformer 52Fl 52F2 ... Main transformer secondary high-voltage circuit breaker 52S ... Transformer secondary circuit breaker 89ST ... Internal transformer switch Tr ... Internal transformer

Claims (2)

  The system interconnects the power company transmission line and the power receiving extra high transmission line from the power station in one line, and the grid connection breaker from the normal power receiving breaker to the main transformer on the power station side An automatic power recovery system in a one-line power receiving extra high power plant, characterized by changing to a secondary high-voltage circuit breaker.   In the event of a power receiving extra high transmission line accident, once the power plant is completely shut down, the main transformer secondary circuit breaker automatically shuts down, and if the power receiving extra high transmission line succeeds in re-transmission, the power receiving breaker and the main transformer secondary circuit breaker As long as a certain period of time has elapsed after receiving power, the secondary transformer's secondary high-voltage circuit breaker can be automatically turned on in sequence and connected to the power generation voltage. An automatic power recovery system in a one-line power receiving extra high power plant according to claim 1, wherein the automatic power paralleling is performed.

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