JP2542386B2 - Power flow monitoring method - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to a power flow monitoring method for power equipment, which protects the equipment of a power system so that the power flow flowing through the equipment does not become excessive.

[Prior art]

Conventionally, as a power flow monitoring method of this kind of electric power equipment, there is one shown in the figure. In the figure, 1 and 2 are bus bars. 3,
4,5 are electric power facilities that connect the bus lines 1 and 2 and correspond to power transmission lines and transformers. X ₁ , X ₂ and X ₃ are impedances of the power equipments 3 to 5. _{K a1, K a2, K a3} , the power equipment 3-5 has a unique installed capacity _{K a1, K a2, K a3} , when indicating the target value _{K b1, K b2, K b3} , K a1 > K _b1 , K _a2 > K _b2 , K _a3 > K _b3 . In addition, P ₁ , P ₂ , and P ₃ are tidal currents flowing through the individual electric power equipments 3 to 5,
P _T is the total flow that flows through the power equipment 3-5.

Generally, the tidal currents P _{1 to} P ₃ that flow through the individual electric power facilities 3 to 5
Is often not given as a measured value, and is monitored using the integrated power flow P _T. The sum of the facility capacities K _a1 , K _a2 , and K _a3 peculiar to each power facility 3 to 5 was used as the total facility tolerance for comparison with the power flow P _T. The sum of the target values K _b1 , K _b2 , and K _b3 specific to each of the power facilities 3 to 5 was used as the target value of the overall facility for comparison with the power flow P _T. That is | P _T |
Was greater than K _a1 + K _a2 + K _a3 , it was overloaded, and smaller was normal. If | P _T | is larger than K _b1 + K _b2 + K _b3 , the target value is exceeded, and if it is smaller, it is normal.

As described above, the conventional power flow monitoring method has a drawback that the number of data of the limit value used for monitoring increases because the limit value of the facility has a unique target value in addition to the unique facility capacity. It was

[Outline of Invention]

The present invention is made to eliminate the above-mentioned drawbacks of the conventional ones, and the limit value data is obtained by performing the total target value monitoring of the facility using only the facility capacity specific to the facility as the limit value. It is an object of the present invention to provide a power flow monitoring method for electric power equipment, the number of which can be reduced.

Example of Invention

An example of this method will be described below. Total equipment flow P _T
As the target value to be compared with, the smaller one of the following values is set as the target value for the overall equipment.

Now, among the tide P ₁ to P ₃ through the power equipment 3-5, if the tide P ₃ through the power equipment 5 and the maximum, on the assumption that the power system 5 is stopped, power equipment 5 is stopped The expected power flow, which is the current flow P ₁ + P ₂ + P ₃ that had flowed before the splitting, is split into the power equipment 3 and the power equipment 4 and obtained. The above assumption can be applied to the power flow overload of each equipment of the power system. Assuming that the expected power flow flowing through the power equipment 3 is the same as the unique equipment capacity K _a1 of the power equipment 3 (own equipment capacity), the overall power flow P of the equipment is expressed as follows.

Similarly, assuming that the expected power flow flowing through the power facility 4 is the same as the unique facility capacity K _a2 of the power facility 4 (own facility capacity), the facility total power flow P is expressed as follows.

As described above, the smaller one of | P | in the equations (1) and (2) represented by using K _a1 , K _a2 , X ₁ , and X ₂ is set as the target value for the overall equipment.

If the measured P _T is monitored with the target value of the total equipment obtained in this way, for example, the electric power equipment 5
Even if the power supply stops, the target value of the overall equipment is monitored so that overload does not occur in the remaining individual power equipment 3 and 4.
This can be performed by using only the facility capacity K _a1 , K _a2 , K _a3 specific to the facility.

It should be noted that in the above embodiment, the number of electric power facilities connecting the buses is three.
Although the case has been described, even if the busbars are connected by two or four or more electric power facilities, the target value of the overall facility can be applied by the following formula.

However, i indicates equipment other than the equipment that shares the maximum power flow.

〔The invention's effect〕

As described above, according to the present invention, for each power equipment other than the power equipment sharing the maximum power flow assumed to have stopped, a power flow equal to its own capacity flows to its own power equipment. The power flow of the overall equipment in the case of assumption is calculated based on the own equipment capacity and the impedance of the power equipment other than the power equipment assumed to be stopped, and the power equipment other than the power equipment assumed to be stopped Set the smallest power flow of the total equipment flow calculated for each as the total equipment target value, and assume that an overload occurs when a power flow exceeding the set target value flows to the overall equipment Therefore, it is possible to determine that an overload has occurred in any of the power facilities without measuring the power flow for each power facility, and the power flow sharing the maximum power flow. Stopping facilities if there is an effect that it is possible to prevent the overload is generated in other power equipment.

[Brief description of drawings]

The figure is a connection diagram showing the configuration of the power equipment to be monitored. 1, 2 ...... bus, 3-5 ...... power equipment, X ₁ ~X ₃ ...... impedance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Omata 1-3-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Co., Inc. Research & Development Headquarters Research Center Development Automation Laboratory (72) Inventor Yoshiwaki Nishiwaki Fuchu, Tokyo Toshiba Town No. 1 in Toshiba Fuchu Factory (72) Inventor Mamoru 52-1 Omika-cho, Hitachi City Stock Company Hitachi Ltd. Omika Factory (72) Inventor Uichiro Goto Wadazaki-cho, Hyogo-ku, Kobe 1-1-2, Mitsubishi Electric Corporation Control Factory

Claims (1)

(57) [Claims] 1. When the target value of the total equipment used for overload determination is set in advance, among the plurality of electric power equipment connected between the busbars, the electric power equipment sharing the maximum power flow is stopped. On the other hand, for each of at least one or more power equipment other than the power equipment assumed to have stopped, it is assumed that a tidal current equal to its own equipment capacity has flowed to its own power equipment. Of the total power flow for each power facility other than the power facility assumed to have stopped, as well as its own capacity and the impedance of power facilities other than the power facility assumed to have stopped. Set the smallest of the tidal currents as the target value for the overall equipment, and determine that an overload has occurred when a tidal current that exceeds the set target value flows through the overall equipment. Trend monitoring method of power equipment.