JPH0652976B2 - Power system stabilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an electric power system for preventing the power generation engine from being broken due to the inability to maintain the synchronization of the power generation engine after the occurrence of an accident and the system being unstable. The present invention relates to a system stabilizing device.

[Conventional technology]

Conventionally, an apparatus of this type has been shown in FIG. In the figure, A is an accident detection end, B is a power plant to be controlled, and CPU is a central processing unit. An accident signal is sent from A to CPU, and a breaking or disconnection command is sent from B to CPU.

Next, the operation will be described. At A, the type of accident is detected by the operation signal of the protection relay and the signal is sent to the CPU. The CPU determines whether or not a part of the generator needs to be turned off or turned off by comparing it with the value of the pre-current flow or a preset accident condition. Issue a command.

[Problems to be Solved by the Invention] Since the conventional power system stabilizing device is configured as described above, when the number of accident detection ends increases, the amount of information to be transmitted increases and it is difficult to determine the conditions to be set. To be
Further, in the case of an accident in the same power transmission line, since the accident points cannot be distinguished, there is a drawback in that it is difficult to accurately determine if the accident points in the same power transmission line differ in disconnection amount or disconnection amount.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional ones, and accurately selects a necessary amount and a disconnection amount from the electric output during an accident of the accelerating generator group and the decelerating generator group. It is an object of the present invention to provide a power system stabilizing device that can be used.

[Means for Solving the Problems]

In the power system stabilizing device of the present invention, when a part of a generator or a generator group that is decelerating is to be stabilized by cutting, the amount k and the amount of disconnection k are determined as follows.

M ₁ , P _M1 , Pe _{1 for} the inertia constant of the accelerating generator or generator group, mechanical input, electric output during accident, M for the inertia constant of the generator or generator group for deceleration, mechanical input, and electric output during accident. ₂ ,
When P _M2 , Pe ₂ , the inertia constant of the generator or generator group that does not accelerate or decelerate is M ₃ , and the ratio of the deceleration of the generator or generator group that slows or cuts is k, X = (P _M1 −Pe ₁ ) / M ₁ Y = (P _M2- Pe ₂ ) / M ₂ Is calculated for some predetermined k, The smallest k that satisfies However,
t is the duration of the accident and E _C (k) is a constant determined by k.

[Action]

According to the present invention, a device capable of easily determining the interruption amount by P _M1 , M ₁ , Pe _{1 of} the acceleration generator, P _M2 , M ₂ , Pe _{2 of} the deceleration generator, and M ₃ of the non-acceleration / deceleration generator Since it has been developed, the device will be inexpensive and highly accurate.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, G1 is a generator group that accelerates, G2 is a generator group that decelerates (including a pumped-storage generator), and G3 is a generator group that does not accelerate or decelerate. Electrical output is M ₁ , P _M1 , Pe ₁ , M ₂ , P _M2 , Pe ₂ , M ₃ , P
_M3 , Pe ₃ and the respective back angles are δ ₁ , δ ₂ , δ
_Set to ₃ .

Further, the CPU indicates the central processing unit, the information A indicates the information sent from the G1 to the CPU, the information B indicates the information sent from the G2, and the information C indicates the information sent from the G3 to the CPU.

Specifically, the information A is M ₁ , P _M1 , Pe ₁ and the information B is M ₂ , P 1.
_{M 2} , Pe ₂ and information C represent M ₃ . In the CPU, using these information, X = (P _M1 −Pe ₁ ) / M ₁ and Y = (P _M2 −Pe ₂ ) / M ₂ Is calculated for some predetermined k, The smallest k that satisfies However, t
Is the duration of the accident and E _C (k) is a constant determined by k.
In this way, the amount of disconnection is determined, the command for disconnection is issued to G2, and the system is stabilized.

The operation of the present invention will be described below.

In Fig. 2, the equation describing each generator is Mi = P _Mi -Pei (i = 1 to 3) (1). In addition, ·· indicates the second derivative.

Here, δ ₀ = (M ₁ δ ₁ + M ₂ δ ₂ + M ₃ δ ₃ ) / M ₁ + M ₂ + M ₃ ) ... (2) θi = δi−δ ₀ (i = 1 to 3) ... (3) If we change the kinetic energy K _M of the whole system, Becomes It should be noted that-indicates one-time differentiation. The replacement of the equation (3) is expressed by the deviation from the average value δ ₀ weighted by the inertia constant because the step-out phenomenon of the power system is determined by the relative relationship of the back angle of the generator.

Here, assuming that the accident duration is t, from equation (1) Becomes Furthermore, for generator G3 without acceleration / deceleration, it is considered that P _M3 −Pe ₃ = 0 ... (7), so = 0, and together with Eq. (6), (5)
Substituting into the expression, Becomes

now Putting that, equation (10) is Becomes

Therefore, assuming that the potential of the unstable equilibrium point after the accident is Ec, it becomes possible to judge that K _M > Ec → unstable (12) K _M Ec → stable.

Next, let us consider a case where a part of the deceleration generator group G2 is turned on or off at the same time as the accident is cleared, and the rate of turning off is set to k.

In this case, it is considered that the inertia constant of the deceleration generator group G2 changed from M ₂ to M ′ ₂ = (1-k) M ₂ (13) immediately after the accident was cleared, so δ ₀ of (2) color is δ ′ ₀ = (M ₁ δ ₁ + M ′ ₂ δ ₂ + M ₃ δ ₃ ) / (M ₁ + M ′ ₂ + M ₃ ) ... (14) And the kinetic energy of equation (5) is Becomes However, equations (6) and (7) do not change.

Therefore, if equation (15) is expressed by X and Y in equations (9) and (10), Therefore, it is possible to determine that K _M ′> E _c ′ → unstable (17) K _M ′ E _c ′ → stable as the potential E _c ′ of the unstable equilibrium point after a part of the deceleration generator group G2 or after disconnection. Here, since E _c ′ is considered to be determined by the inertia constant M ′ _{2 of} G2, that is, the breaking ratio k, E _C (k) is obtained in advance. As Becomes It means that the smallest k should be selected as the amount of cut.

In the above embodiment, M ₃ is also included as the information C in FIG. 1, but this can be set to a constant value and the transmission path of the information C can be omitted.

Similarly, in the information A or B of FIG.
The same effect can be realized by transmitting only P _M1 −Pe ₂ P _M2 −Pe ₂ instead of P _M1 , Pe ₂ , P _M2 , and Pe ₂ .

Also, in the information A of FIG. ₁ , a method in which M ₁ is set to a constant value and M ₁ is not transmitted may be considered.

If there is no generator group G3 that does not accelerate or decelerate, M ₃ =
It is possible to use this method as 0.

[Effects of the Invention] As described above, according to the present invention, P _M1 , M
₁ , Pe ₁ , the speed reducer generators P _M2 , M ₂ , Pe ₂ and the non-acceleration / deceleration generator M ₃ have been developed to make it easier and determine the disconnection amount, so the device is inexpensive and highly accurate. There is an effect that can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a power system stabilizing device of the present invention, and FIG. 2 is a diagram showing a system configuration of a conventional power system stabilizing device. In the figure, G1 is a generator group that accelerates, G2 is a generator group that decelerates, G3 is a generator group that does not accelerate or decelerate, and CPU is a central processing unit.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shigefumi Maruyama 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Toshio Kasahara 1-1-11 Baba-dori, Utsunomiya-shi, Tochigi Tokyo Electric Power Co., Ltd. Tochigi Branch

Claims (1)

[Claims] 1. When stabilizing a power system by stabilizing or cutting off a part of a generator or a group of generators to be decelerated, the amount of breaking or breaking is determined as follows. Power system stabilizer. M ₁ , P _M1 , Pe _{1 for} the inertia constant of the accelerating generator or generator group, mechanical input, electrical output during accident, M for the inertia constant of the generator or generator group for deceleration, mechanical input, and electrical output during accident. ₂ ,
When P _M2 , Pe ₂ , the inertia constant of the generator or generator group that does not accelerate or decelerate is M ₃ , and the rate at which the generator or generator group that decelerate slows or cuts is k, X = (P _M1 −Pe ₁ ) / M ₁ Y = (P _M2- Pe ₂ ) / M ₂ Is calculated for some predetermined k, The smallest k that satisfies However,
t is the duration of the accident and E _C (k) is a constant determined by k.