JP2009124911A - Power-feeding controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power-feeding controller which keeps supplying power to an emergency power bus line load without bringing the in-station power generator to a stop even when a breaker in a substation on the transmission system side is opened and a power interruption is caused due to an interruption of incoming power during parallel operation of the transmission system from the substation and an in-station power generator. <P>SOLUTION: The power-feeding controller includes: a power interruption detecting means which is configured to supply power to the emergency power bus line load and to a regular power bus line load other than the emergency power bus line load and detects the occurrence of power interruption on the transmission system during parallel operation; and a load cut-off means which, based on a detection signal from the power interruption detecting means, cuts off the regular power bus line load from a power generator. The power interruption detecting means commits no malfunction in detecting power interruption and detects a power interruption at high speed, so that the occurrence of power interruption is recognized when a purchase power drops below a minimum purchase power. The load cut-off means is configured to ensure high-speed cut-off, so that a load to be cut off is selectively forecasted to allow the power generator to operate continuously without excessive fluctuation of a load to the power generator during a synchronous operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply control device configured to supply power to a load by parallel operation of a power transmission system from a substation and an on-site generator, and in particular, continues even when a power failure occurs in the power transmission system. The present invention relates to a power supply control device for continuing power supply to an emergency power supply bus load or an important load.

In conventional power supply control devices configured to supply power to the emergency power bus load and other general power bus loads, a power failure occurs in the power transmission system during parallel operation of the power transmission system and the on-site generator. In such a case, it is detected that a power failure has occurred and a means for disconnecting the general power supply bus load from the in-house generator is taken based on the power failure detection signal within a predetermined time (see Patent Publication 1).
The reason why the general power bus load is disconnected from the on-site generator is that the on-site power generator supplies power to the emergency power bus load and other general power bus loads when a power failure occurs in the transmission system. This is to avoid an overload state of the machine itself, which causes power supply to be disabled, resulting in a power failure.

However, there are cases where the amount of power used by the emergency power bus is greater than the amount of power generated by the generator connected to the emergency power bus. In this case, even if it is detected that a power failure has occurred and a means for disconnecting the general power bus load from the on-site generator is taken within a predetermined time based on the power failure detection signal, the on-site generator will continue to be overloaded. There is a problem that the generator itself is damaged, or that the automatic stop function is activated when the overload state continues and the emergency power supply bus load equipment is stopped.
Generally, power failure detection is performed using an undervoltage relay, etc., but in that case, the power failure detection time is as long as seconds from the standpoint of preventing malfunctions, so the disconnection of the general power bus load is delayed, and the generator There is a problem that the possibility of normal operation is low.

Japanese Utility Model Publication No. Hei 6-41350

  In order to cope with the above-mentioned problems, the present invention cuts off the supply of received power by opening the circuit breaker of the substation on the power transmission system side during parallel operation of the power transmission system from the substation and the on-site generator. An object of the present invention is to provide a power supply control device capable of continuously supplying power to an emergency power supply bus load without stopping an on-site generator even when a power failure occurs.

In order to achieve the above object, the power supply control device of the present invention is configured to supply power to an emergency power supply bus load and a general power supply bus load other than the emergency power supply bus load, respectively. In a power supply control device comprising a power failure detection means for detecting occurrence and a load interruption means for separating the general power supply bus load from the generator based on a detection signal from the power failure detection means, the load interruption means is in operation. The power supply control device or the central monitoring device determines the power supply target load from the actual power used before the power failure of each load of the emergency power bus load so that the load becomes 65 to 85% of the total capacity of the generator . A load other than the load to be fed is cut off.

  When the power failure detection means is activated, the emergency circuit bus and the general bus are disconnected and the emergency power bus is operated independently.However, based on the power failure detection signal, the general power bus load is disconnected from the generator, and the emergency power bus When power is supplied only to the load, it is expected that the generator will be overloaded in an emergency power bus load configuration where the power usage of the emergency power bus is greater than the generator power generation connected to the emergency power bus. The

For this reason, the load to be fed is determined from the actual power used before the power failure of each load of the emergency power supply bus load so that it becomes 65 to 85% of the total capacity of the generator in operation, and other loads It was decided to cut off.
Here, two reasons why the load is 65 to 85% of the total capacity of the generator in operation will be described. The first reason is that the load fluctuation is taken into consideration. The second reason is that the power quality is taken into consideration. When a power failure occurs, the generator is overloaded until the load is cut off, so the number of revolutions of the prime mover connected to the generator decreases slightly, so the generator load is reduced by 15 to 35% (ie The load is 65 to 85% of the capacity of the generator.) By this, it is possible to shorten the time from when the rotational speed is reduced to when the rotational speed is increased to the specified number of times, thereby improving the quality of the power supply.

Here, the power failure detection means described above is preferably a means for detecting that the amount of received power has decreased to a predetermined rate.
The reason for detecting a power failure as a power failure detection means triggered by a decrease in received power from the power transmission system is to detect a power failure in milliseconds. If the disconnection of the generator's connecting bus is cut off in 200 milliseconds or less from the detection of power failure to the shutdown, and the emergency bus is operated independently, the generator can continue to withstand overload and supply power to the emergency power bus load. Therefore, it is necessary to detect a power failure in milliseconds.
In addition, there is an undervoltage relay or the like as a commonly used power failure detection means, but in this case, the power failure detection time is in seconds as described above, and the connection bus disconnection of the generator is 200 milliseconds or less from the power failure detection to the cutoff. It is difficult to block with.

  Specifically, it is more preferable to detect that the amount of received power from the power transmission system has decreased to 40% or less of the minimum amount of power used. For example, in the case of a minimum power purchase power of 500 kw, a power failure occurs when the power purchase amount falls below 200 kw. This is because an instantaneous load fluctuation of the emergency power supply bus load may be 50 to 60% of the minimum power consumption, and a malfunction caused thereby is avoided.

Specifically, the load shut-off means sends the actual value data before power failure of each load of the emergency power supply bus load to the remote central monitoring device, and the central monitoring device based on the actual value data When a power failure is detected, it is preferable to shut off loads other than the power supply target load.
When the actual value data of each load of the emergency power supply bus load is transmitted to the central monitoring device for monitoring, determining the power supply load on the central monitoring device side from the actual value data before the power failure To do.
Here, the method for determining the load to be fed is to set the priority parameters for each load in advance, and add the actual power used before power failure for each load from the highest priority. A load up to 70 to 80% of the total capacity value of the generator is set as a power supply target load.

  Moreover, it is preferable to use a direct acting type vacuum circuit breaker whose opening / closing operation time is a predetermined time or less for the load breaking in the load breaking means described above. Using a direct-acting vacuum circuit breaker makes it possible to perform opening and closing operations in tens of milliseconds. Combined with control by a high-speed sequencer, the time from power failure detection to actual load interruption Is about 100 milliseconds. Since the disconnection of the connecting bus of the generator can be interrupted in 200 milliseconds or less from the detection of power failure to the interruption, the generator can withstand an overload and continuously supply power to the emergency power bus load.

  Further, in the above-described power supply control device, the operation from the power failure detection by the power failure detection means to the load interruption by the load interruption means is performed within 200 milliseconds, so that from the power failure detection to the load interruption operation. During this time, the generator will withstand overload and be able to continuously supply power to the emergency bus.

  According to the power supply control device of the present invention, even when a power failure occurs in which the breaker of the substation on the transmission system side is opened and the supply of received power is cut off, the power usage of the emergency power supply bus is connected to the emergency power supply bus. Regardless of the configuration of the emergency power bus load that exceeds the generator power generation amount, it is possible to continuously supply power to the emergency power bus load without stopping the on-site generator. There is an effect that can be done.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the scope of the present invention is not limited to the illustrated examples.

In FIG. 1, one Example of the systematic diagram of the electric power feeding control apparatus of this invention is shown.
In FIG. 1, a premises communication bus load is connected to the power transmission system 8 via a main circuit breaker 6. The local communication bus load is composed of an emergency bus load 20 and other general bus loads 30. The emergency bus load 20 receives power from the emergency bus 2, and the general bus load 30 receives power from the general bus 3. A bus bar breaker 7 is provided between the emergency bus 2 and the general bus 3. The power supply control device 1 is configured to supply power to the emergency power supply bus load 20 and the other general power supply bus load 30, respectively, and a power failure detection means 4 that detects that a power failure has occurred in the power transmission system 8 during parallel operation. The load interrupting means 5 for disconnecting the general power bus load 30 from the generator based on the detection signal from the power failure detection means 4 is provided. This power failure detection means 4 detects a decrease in the amount of received power from the power transmission system 8. Further, the load interrupting means 5 determines the power supply target load from the actual power used before the power failure of each load of the emergency power bus load 20 so that the load is 70 to 80% of the total capacity of the generator in operation. Shut off other loads.

Here, an algorithm for determining the power supply target load from the actual power used before the power failure of each load of the emergency power bus load will be described with reference to FIG.
As shown in FIG. 2, for example, there are five loads a1 to a5 as emergency power supply bus loads, and the priority (importance) is high in order of priority from a3 → a2 → a1 → a5 → a4. Is set. Before the power failure, two generators (G1, G2) are operating, and the total capacity value of the generators is 1200 kW. Also, consider the three cases shown in Table 1 below as actual power consumption values for each load before a power failure. Moreover, a load interruption means shall determine electric power feeding object load from the used electric power actual value before a power failure of each load so that it may become 80% load of the capability total value of the generator (G1, G2) in operation.

  In the case of the above assumption, in case 1, the total used power value of each load before the power outage is 1150 kW, and the total capacity of the operating generator is less than 1200 kW. Even if power is supplied, the generator will not be overloaded. However, even in this case, since load fluctuation is expected, considering load fluctuation and power supply quality, 80% of the total capacity of the generator in operation, that is, 1200 × 0.8 = 960 kw The load is the power supply target load. In this case, when the actual power usage values are added in descending order of priority (a3 → a2 → a1 → a5 → a4), the total value of the actual power usage values a3 → a2 → a1 → a5 is 950 kW. Therefore, these four loads are set as power supply target loads.

  Next, in Case 2, when the total power used by each load before the power outage is 1250 kW, the total capacity of the operating generator exceeds 1200 kW, and power is supplied to all loads (a1 to a5). The generator will be overloaded. In this case, when the actual power usage values are added in descending order of priority (a3 → a2 → a1 → a5 → a4), the total value of the actual power usage values a3 → a2 → a1 → a5 is 950 kW. Therefore, these four loads are set as power supply target loads.

  Similarly, in case 3, the total power usage value of each load before the power outage is 1250 kW, and the total capacity of the operating generator exceeds 1200 kW, and power is supplied to all loads (a1 to a5). In some cases, the generator is overloaded. In this case, when the actual power usage values are added in descending order of priority (a3 → a2 → a1 → a5 → a4), the total value of the actual power usage values a3 → a2 → a1 becomes 900 kw, and a3 → Since the total value of the actual power usage values of a2 → a1 → a5 is 1050 kW, the three loads a3, a2 and a1 are set as the power supply target loads.

  Next, the operation of the power failure detection means 4 will be described. The power failure detection processing flow of the power failure detection means 4 is shown in FIG. As shown in the flow of FIG. 3, the power failure detection process constantly monitors (monitors) the received power from the power transmission line of the power transmission system 8 (step S11). When the received power from the transmission line falls below 40% of the minimum power consumption, it is recognized as a power failure (step S12), and a power failure detection signal is output (step S13).

  Next, the operation of the load interrupting means 5 will be described. FIG. 4 shows a load cutoff process flow of the load cutoff means 5. As shown in the flow of FIG. 4, in the load shedding process, the actual value data of each load of the emergency bus load is read (step S21). The actual value data is read by the power supply control device or the central monitoring device. A signal cable or a communication cable is used as a method of transmitting performance value data to the central monitoring device.

  Next, the load to be fed is determined so as to be a load of 65 to 85% of the capacity (total value) of the generator from the actual value data of the feed power of the feed control device (step S22). This determination is performed by the power supply control device or the central monitoring device. The algorithm for determining the load is as described above. When a power failure is detected by the power failure detection means 4 (step S23), loads other than the power supply target load determined in step S22 are blocked (step S24).

  FIG. 5 shows a schematic system configuration of the power supply control device and the central monitoring device. As shown in FIG. 5, there are a case where the central monitoring device and the power supply control device are connected by a communication network (FIG. 5 (1)) and a case where they are connected by a signal cable (FIG. 5 (2)). In the case of FIG. 5 (1), the power supply control device transmits the power failure detection signal and the actual power usage value of each load to the central monitoring device using the data communication means, and receives information on the power supply target load from the central monitoring device. Receive data. In the case of FIG. 5 (2), the power supply control device outputs a power failure detection signal and the actual power usage value of each load to the central monitoring device, and inputs information on the power supply target load from the central monitoring device.

  The power supply control device or the central monitoring device predicts from the actual value of the power supply of the power supply control device before the power failure, and determines the power supply load in advance according to the power supply capability of the operating generator. The on / off sequence of the individual load circuit breaker for each load waits for a power failure, and the individual load circuit breaker for the emergency bus load is turned on and off simultaneously with the detection of the power failure to control the load on the emergency bus load.

Specifically, the load interrupting means can control for 100 milliseconds by using a high-speed A / D power converter, a direct acting vacuum circuit breaker, and control by a sequencer. The grounds that 100 milliseconds can be blocked will be described in detail below. First, the time required for high-speed A / D power conversion is 20 milliseconds or less. Further, the time required to open and close using the direct acting vacuum circuit breaker is 40 milliseconds or less. Furthermore, as a performance specification of the sequencer, if a device with an operating time of 10 milliseconds or less from the input of received power reading data to the output of the circuit breaker switching command is adopted and configured in hardware, about 70 after the received power is reduced (power failure detection). The communication bus can be cut off in milliseconds.
In other words, with the detection of a power failure of the commercial power supply as a trigger, the opening speed of the contact breaker between the emergency bus and the general bus is shut off at a high speed of 100 milliseconds or less, and the generator is independent from the parallel operation with the transmission system from the substation. It switches to driving.

Also, as a power supply method in the event of a long-term power outage, if power is supplied to the emergency bus load and the generator has surplus power, the power supply control device or the central monitoring device will use the predicted load values for the emergency bus load and general bus load. Is calculated, and the emergency bus load and general bus load are shut off and turned on to limit the load within the range of the maximum supply capacity of the generator.
If there is a generator that is stopped and the power supply to the emergency bus load and general bus load is insufficient, start the generator that is stopped and load the load separately according to the predicted power output. Turn on the circuit breaker.

  The power supply control device of the present invention is configured to supply power to a load by parallel operation of a power transmission system from a substation and an in-house generator system, and the power usage of the emergency power supply bus is connected to the emergency power supply bus. This is useful for a power supply control device having an emergency power bus load that is greater than the amount of power generated by a generator. It is also useful in the configuration of an emergency power bus load that is smaller than the generator power generation amount.

Example of system diagram of power supply control device of the present invention Algorithm for determining the load to be fed from the actual power consumption before the power failure Power failure detection process flowchart Load cutoff process flowchart Schematic system configuration diagram of power supply control device and central monitoring device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power supply control apparatus 2 Emergency bus 3 General bus 4 Power failure detection means 5 Load interruption means 6 Main circuit breaker 7 Bus connection breaker 8 Power transmission system 9 Individual load circuit breaker 20 Emergency bus load 30 General bus load

Claims (6)

  A power failure detection means configured to supply power to the emergency power bus load and a general power bus load other than the emergency power bus load, and to detect that a power failure has occurred in the power transmission system during parallel operation, and the power failure detection means In the power supply control device provided with the load shut-off means for disconnecting the general power supply bus load from the generator based on the detection signal by the load, the load shut-off means becomes a load of 65 to 85% of the total capacity value of the operating generator. As described above, the power supply control device or the central monitoring device determines the power supply target load from the actual power consumption value before each power outage of each load of the emergency power supply bus load, and cuts off the load other than the power supply target load. A power supply control device characterized by the above.   The power supply control device according to claim 1, wherein the power failure detection means is means for detecting that the amount of received power from the power transmission system has decreased to a predetermined rate.   The power supply control device according to claim 1, wherein the power failure detection unit is a unit that detects that the amount of received power from the power transmission system has decreased to 40% or less of the minimum amount of power used.   The load interrupting means sends actual value data before power failure of each load of the emergency power supply bus load to a remote central monitoring device, and the power supply target load is determined in the central monitoring device based on the actual value data The power supply control device according to claim 1, wherein when a power failure is detected, a load other than the power supply target load is selectively cut off.   The power supply control device according to claim 1, wherein the load interruption in the load interruption means uses a direct acting vacuum circuit breaker whose opening / closing operation time is a predetermined time or less.   The power supply control device according to any one of claims 1 to 5, wherein an operation from a power failure detection by the power failure detection means to a load interruption by the load interruption means is performed within 200 milliseconds.